The idea is to make the losing side more powerful while allowing the winning side to hold its own.
Not sure how the %'s would work, it could result in a clear win either side by that side getting the good odds.
There are three setups I'm deveolping:
1. The % of each powerrole increases as that side loses (i.e. the docs chance to protect increases as townies die)
2. Powerroles appear as that side loses (i.e. mafia are all goons and town are all vanillia at start)
3. Powerroles improve (rolename cop becomes cop, jailer becomes doc, tracker becomes vig)
If you'd be willing to discus this with me shoot me a PM I'd love to talk about it.