I can’t wait to see the pictures of your progress! The last thread I read about Berghia nudis was basically a pictorial of the battle from start to finish and it was awesome!
I am by no means a Berghia expert, or an expert of any kind for that matter, but I think you may have better success with even more nudi’s. If your invasion is as bad as you say it is, then I think you can probably sustain them. You may consider thinning the herd as the aiptasia population dwindles, but I think you would also benefit from an expedited aiptasia annhilation.
Do you have a plan for your nudi’s after the aiptasia problem is handled, assuming that occurs before they reach old age naturally?