Secondary head touching the printed parts

I have taken the time to loosen both heads and by slightly (+/- .5mm) spacing the secondary head with a metal washer which still means that it is close enough to the print bed to print support material or secondary colours or such but will not touch the printed parts as long as you properly level the print bed with the primary nozzle.

I have also overcome the parts lifting problem by cleaning the print bed with Acetone as soon as you see this starting to happen or every now and again depending on how much you are printing.I am printing almost non stop and clean the print bed about once a week, if you touch the print bed with your hands you have to clean it because your hands are naturally oily.