I think we will need to handle base traits for rchars a bit differently than other stuff. If we'll use our usual "healer:30 mage:30 warrior:30", there will be a huge disbalance in classes. Since a char can only have 2 base traits, those possible traits that go after first two traits in rchar json will be much rarer than the first two.
And it also will lead to very high chance of double base traits, with the chance to have one single base trait close to 0.
I suppose it should be something like our rts function for GMs that selects a random value independently from others, no matter their order. And there probably should be either hardcoded or tunable chance of having only 1 base trait.