For Europe all Kodak chemistry is made in Germany for Eastman Kodak, Geneve, so it's not made by Champion.
Liquid chemicals I'm pretty sure they are outsourced to Tetenal.
About packaging sizes....
I used to stress over this but now I don't. D-76 in 1 liter package costs $4. D-76 in 1 gallon (3.8 liters) costs 6 dollars. XTOL in 5 liters cost 10 dollars. Unless you ONLY process few rolls, D-76 in 1 liter bag is the most expensive option.
Assuming using undiluted and 8 oz per one roll of 35mm, you can process 4, 15, and 20 rolls respectively. If you store them in a bunch of 8 oz bottles, they last minimum of 6 months, more like 12 months. If you choose bottles made of RIGHT plastic, these are good enough for this purpose. It doesn't necessary has to be glass.
Even if you don't use them all up in 6 months to a year, it will probably represent the smallest part of your photographic expense.
By the way, I currently use a system of bottles that consists of 1 1/2 gallon bottle, 2 1 liter bottles, and 4 8 oz (250cc) bottles. Total, it'll store just about 5 liters. I start using from the smallest bottles. Once they are all empty, I decant larger to smaller. This way, all bottles are always full and exposure to fresh air happens 3 times at most and very briefly. Using this method, I had all developer last longer than 8 months. (I usually run out at this point)
I just suggest using developers you like and forget the cost. It's not enough to worry about.
As I was reading along I thought you were going to say that after you use an 8 ounce bottle the first week, you keep rolling so that you use a 1 liter bottle the next week and a half gallon the week after.
I don't know about you but the first quart lasts me a while... then the next three quarts seem to vaporize. (Because once I get going - I keep moving).
If you're going to push Tri-X I suggest Diafine. Tri-X at 1250 looks pretty darn good and the 2 bath action prevents the highlights from just becoming empty blobs.