Actually 32-bit signed integer overflows at 2147483647. Unsigned overflows at 4.294.967.295.
Anyway, i've also been having an hard time reeinforcing my squad. I usually can only bid at high traffic hours, so i end out quiting on a player after the first round, when i see how many people bid at the last second...
In order to complete my squad, i went for a couple of 3*, free transfer, old players. They're doing the job, at low cost, and no token war. Problem is replacing 1st squad players.