Couldn't you just event it?
condition branch BIG WALLET in inventory
if in inventory
conditional branch player's gold = 100 or above
above 100: change gold=100
below 100: add gold +1
if not in inventory
conditional branch player's gold = 50 or above (let's say that 50 is the limit for your first wallet)
above 50: change gold=50
below 50: add gold +1 (or however much you want to give away)
then, as for the battles where you obtain gold, make sure to put a parallel process for whatever maps have battles on, and then "limit" the gold again! (conditional branch big wallet, if not then limit to small wallet (50 gold).
In theory, this should work.
Just edit if you have a large amount of wallets.