1b) An improved idea (and the one Doog was favoring) was to ask users to select one of a few options for maximum bet. For example, you would chose if you want 0.5% maximum wagered per bet or 1%. The site then just has to calculate the percentage of the bank roll owned collectively by those two bins after every roll since the percentage a single investor owns of either bins remains a constant unless there is an invest or divest event. This, for now, seems to be the way it may be implemented.
1b looks OK. If someone wants to go into higher risk bin and take on themselves percentage of all bets above current Max Profit it's fine with me.
This has all been hashed over before. Max profit should be returned to the kelly optimum of 1%, and investors should be encouraged to reduce their investment size until they no longer have hernias when a whale wins big. There is no need for an additional risk limit knob -- that's what your investment amount is for.