Dear Bennet,
Welcome to the forum. In answer to you information request, I use a lot of oils (but not exclusively). I have not used the Abteilung oils so I really cannot comment on them. I know however that they are a good respected make in the world of AFV Painting and weathering. As others have said, there is a multitude of makers of oil paints from basic student lines to oils that have been manufactured similar to the Old Masters, and with the corresponding price tag!
If you are serious about using just oils then I would not start with the student paints. The reason is this. The "professional" paints have a much higher pigment ratio and can be thinned down to an amazing degree for glazes etc. A large part of of oil painting is mastering this layering technique.
I would also experiment with the drying times of the paint. This can easily be speeded up with the use of Liquin. Depending on how much is used, you can make the paint rapidly set. If you mix mediums and want to add an area of acrylic paint then you will have to Matt varnish the oils otherwise the acrylic paint will ball up rather like water on a waxed surface. I recommend Testors Matt Varnish. It comes in small shake and spray cans, dries very quickly and is dead flat Matt. Highly recommended.
I would start by using the Windsor & Newton range. They are readily available and are often cheaper to buy online. They are consistent and are available in different tube sizes as well as a myriad of colours. As Steve said in the above post, a little goes a long way so there really is no need to buy the monster sized tubes, however tempting the Christmas sales offer may be! As your experience grows you might branch out into other brands for more specialist colours. Assuming that the top is properly closed, they have a pretty indefinite shelf life.
I use sable brushes. Yes they are expensive, but if you look after them they will last you a long time. After a session I clean off the excess paint using real turpentine and then use B&J "The Masters Brush" Cleaner and Preserver ( available from all good Art shops as well as Amazon) This resembles old fashioned shaving soap and really does help preserve the brushes. I would avoid the white hog haired brushes as even the finest of them is just too coarse. Before I forget, I would also recommend a fan shaped brush. This rather resembles a false eyelash on a stick! It is used to ever so gently tease out and feather edge the paint when shading. I used this technique when painting the grey horse in one of my earlier posts.
Finally, I would like to recommend this book. It is, The Painter's Handbook by Mark David Gottsegen ISBN: 978-0-8230-3496-3
The book is primarily for the artist painter of portraits, land scapes and so on. It covers the use of oils, acrylics, pastel use, pigments and so on. Any technique you can think of is covered. Yes, a lot of the contents you probably will not use but it truly is a mine of information. If you go for it, get an earlier edition second hand from Amazon / Ebay as they are much cheaper.
Have a great time on the forum. I look forward to seeing some of your work in the future.
Cheers,
Paul