You're not likely to need a 9 kilo servo for each aileron! I'm building a 90 plane with two DS8321 on the tail and I have two DS8301 for ailerons. I think it's overkill and would be better suited for a 2-meter. That's why I bought them, so I'd have some when the 2-meter day finally comes

I have another 90 size plane with 4 std hitec servos, none of which have ball bearings. It flies great. Don't ruin yourself on servos. Hinge properly and seal the gap. That's what makes the difference. It wasn't very long ago the 60-size, and even 1.20 size planes flew very well indeed with only 4 kg servos. I've flown 60-90 size aerobats for years with 4 kg std servos and not once had flutter or servo failure.