Yeah, with 21t of boosters you're going to struggle to hit OM with the EPs even with Drive Distributors. So at 100t combat weight the 3As are probably better. Cooler and less draw I think as well.
If I could make one suggestion it's to use heavy duty on your bulkheads. Since lightweight alloy weighs nothing, there is zero drawback to HD'ing them. Your shields are strong, but a little integrity to fall back on is good, especially as the armor hardness is so low.