The copper will set up a nice little galvanic cell with your aluminium.
Use "Hard racing" or one of the other hard scrub-able AFs. Be sure to use a proper primer and barrier coat first though. Most of the paint manufacturers sell appropriate products for this.
Aluminium based antifoul which is hard, the same stuff used on aluminium hulls and leave atleast 250mm - 300mm square onto the hull area from the sail drive.
Pretty much all the antifoulings are copper based today. For aluminium you want one based on copper thiocyanate and not copper oxide. Most of the eroding antifoulings are copper oxide but so are some of the hard ones too. It should say on the tin if it is suitable for aluminium. Whichever one you use make sure the primer on the saildrive is in good condition first to act as a barrier between aluminium and the antifouling