Big River Bet Strategy Question

[pohuist]

I am going to play in a non-standard game with a big bet allowed on the river. Usually, in this structure the river bet is up to twice the size (for example in a 15-30 game you can bet/raise any amount between 30 and 60). The little I read about such games is that you are supposed to always bet the same amount and typically the maximum if you bet/raise.
The problem I have is that in this particular game one can bet anywhere between 30 and 100 wich is very steep for a 15-30 game. I am looking for advice on the amount I should bet to give my good hands a chance to get paid off and at the same time not being too invested so that I can bet/fold if I smell I am beat.
Any input much appreciated.