Played some games in my KV5 and SU122-44 with mission-earned prem acct, and here's my exp with these two tanks in regard to their silver-making. For KV5 I carried 6 shells of prem ammo, for the SU I carry 3. With KV5 I average about 70k per battle, with lows in the 40k and highs in the 100k. Upkeep cost is about 34k if I used all 6 shells, around 14k if I don't use them. For SU I average around 50k, with highs around 70k and lows around 30k. Upkeep cost is around 20k with prem ammo, around 10k without. I'd love to try a Lowe or T34, but can't justify the cost.
I hardly play my T110E5 now since it's not as good as it first came out, and seems it's outclassed by newer tanks. Just played a game in it for the American line mission and had an awesome game in it. 6800 damage, 8 kills, Steel Wall (14/3/11). It was a close game, my heart was still pounding really fast after it ends. It's this kind of battles that keeps me coming back to this game.