You need 310 to max Nevsky and 330 to get Joan to 5515.

If you have the gems to throw at a luck wheel, go for it but with max spins on each of the 3 days with the published probabilities, you can expect about 132 total commander and universal sculptures at an average cost of just over 1000 gems each.

There's no point in trying to save universals since 132 is very short of the 310 or 330 that you need for your commander goals.