merlyn

If you are searching the German ebay pages for boots  there are some key words to use.
 
The German word for boot is Stiefel.
The German word for leather is Leder. Don't be fooled by synthleder that's the not leather stuff.
NVA stands for Nationale Volksarmee and was the name used for the armed forces of the GDR. ( East Germany before the reunification)
 
 
knobelbecher ( will get you mainly the boots used for TIE pilots, the ones with the straps at the calf)
Seestiefel ( same as above but because people call the boots by different names it brings up different offers)
NVA Parade Stiefel ( this search will bring you the taller, straight shaft parade boots with no strap at the calf, these boots are generally shorter than riding boots but taller than knobelbecher although some people call them the same thing)
NVA Stiefel ( same as above but a broader search parameter)
Schaft stiefel ( this search will get you straight legged boots from right across the board. It's the broadest word you can use to search for the kind of boots most of the people here look for)
offizier stiefel  (This brings you officer boots from also right across the board and also from across many time periods and countries)
Reitstiefel   ( this is the word for riding boots and this is what you will get)

This page ( all in German) has an excellent size chart at the bottom for the various sizes ( normal EU, Bundeswehr, US, Uk and it will help navigate some of the standard sizes you will see.  If you are looking for riding boots or officer's boots you also need to consider calf width this is known as Wadenweite in German so if you are looking at boots this is the word to look for and the measurements will always be given in CM as Europe doesn't do inches. 
https://www.freudenberg-shop.de/shop_content.php/coID/15/item/14  Please note I'm not advertising this shop, it just has the best comparison table. 
By riding boots you will seriously need to watch out for synthetics as there are a lot of those mixed in with the leather ones. You can search for echt leder ( real leather) and that will narrow it down a lot. 

I hope this helps a bit.

There are a billion ways to do the same thing, you will figure your own method out. You will find the comfortable way to tip, turn and hold the fabric while you get the foot where it needs to go. You can always undo mistakes ( except for cutting too small then that's a whole other ball game) that's what your stitch ripper is for. Believe me I have undone my fair share of not sewn right things. What works for me may not work for you, it's trial and error and practice. You will get the hang of it and soon you will be joining the ranks of mad hatters like the rest of us.

my machine has a free arm, if you don't have that then you have a flatbed machine but it shouldn't make a huge difference, you just need to figure out the best way to handle the fabric and I would suggest doing practice runs. I made 5 hats at the very start none of which were very good, two of which were way too small because I had printed out the paper the wrong size. It's tricky until you figure it out then it isn't. Pin everything really well, pinning is vital, your machine can sew over pins if the are perpendicular to the presser foot and if you go slowly. Slow and stead is the key when you are beginning with these, there are lots of curves so it requires that you ease the fabric into being curved. You will get the hang of it and your hat that you showed looks SO much better than my 1st one so you are already way ahead of the game.

I made a tutorial for hat making you can see the pictures here and I show you how I top stitch the crown. Maybe this helps a bit.
 

There is a member, Kodiak,  over on the Jolly roger forum who used leather repair gel and show polish to fill the holes, it did an amazing job. The thread is here if people are members they can read it http://www.jrs501st.com/forums/viewtopic.php?f=8&t=12578&sid=3a5914cf1ffa9fe7e0fb33659ac2ccc8 I have a few pairs of knobelbecher here that I will sell and one of them also has these holes so I will try this fix as well.  If you are looking for these boots when you search ebay.de also look for seesteifel and if you want officer style you can search for Offizierstiefel or paradestiefel. 

I think that any good leather repair paste use to fill holes and large tears will probably work and then just polish them up. 

If you are searching the German ebay pages for boots  there are some key words to use.
 
The German word for boot is Stiefel.
The German word for leather is Leder. Don't be fooled by synthleder that's the not leather stuff.
NVA stands for Nationale Volksarmee and was the name used for the armed forces of the GDR. ( East Germany before the reunification)
 
 
knobelbecher ( will get you mainly the boots used for TIE pilots, the ones with the straps at the calf)
Seestiefel ( same as above but because people call the boots by different names it brings up different offers)
NVA Parade Stiefel ( this search will bring you the taller, straight shaft parade boots with no strap at the calf, these boots are generally shorter than riding boots but taller than knobelbecher although some people call them the same thing)
NVA Stiefel ( same as above but a broader search parameter)
Schaft stiefel ( this search will get you straight legged boots from right across the board. It's the broadest word you can use to search for the kind of boots most of the people here look for)
offizier stiefel  (This brings you officer boots from also right across the board and also from across many time periods and countries)
Reitstiefel   ( this is the word for riding boots and this is what you will get)

This page ( all in German) has an excellent size chart at the bottom for the various sizes ( normal EU, Bundeswehr, US, Uk and it will help navigate some of the standard sizes you will see.  If you are looking for riding boots or officer's boots you also need to consider calf width this is known as Wadenweite in German so if you are looking at boots this is the word to look for and the measurements will always be given in CM as Europe doesn't do inches. 
https://www.freudenberg-shop.de/shop_content.php/coID/15/item/14  Please note I'm not advertising this shop, it just has the best comparison table. 
By riding boots you will seriously need to watch out for synthetics as there are a lot of those mixed in with the leather ones. You can search for echt leder ( real leather) and that will narrow it down a lot. 

I hope this helps a bit.