I would donate for that possibility if dooglus would be willing to implement it. Perfectly would be a kelly percent you can chose freely, not even fixed values to chose from. For gamblers it wouldnt change anything than most probably the max profit. For investors wouldnt change anything either except they want to. And the calculation behind would be done automatically by the site.
To be on the sure side there should be a warning so that noobs dont complain later when the risk didnt work out.
At the end i believe anyone can only win with it. Gambler can play higher, investors can play riskier or play safe and the attracted gamblers would lead to dooglus getting more profit. Win-Win-Win.