[jimcarry]

Cg
Lets see if I can help you here.
All aluminum parts will have to have zincate . The plastic will have to have silva spray or conductive paint also after you zincate these parts you will have to use a strike coat of flash copper or nickle the acid copper to build up the surface this will make it smooth then lightly polish and Copy Chrome can be plated on to the item . Because the plastic is nonconductive the plate will only go where the silva spay is .
When doing parts that will receive high temp I recommend using copper to help disperse heat
as far as plating different metals together I have not tried this .
When I plate nuts or bolt I usually place them in with the larger parts .
I have had a great deal of success with the Copy Chrome plating at between 95 and 110 degrees.
i have done many parts that had to be flipped and they come out fine
I hope this helps good luck