I understand Roth is ultimately taxable, but if profit sharing at first, is it not subject to the 25% deduction limit that would otherwise apply? Or are you assuming based on the numbers above that it's an issue in this case?
I think the simplest way (and what gets done the most? opinions?) is contribute VAT and then do immediate in-plan Roth conversion before any investment experience, leave in the plan as Roth and not even bother with IRA.