Dave: For what it's worth, I've found the Z5 makes for a good base for the Z2 Pro on my black truck. When I first started using Zaino my truck looked great with 3 coats of Z5 on it. However, when I applied 3 coats of Z2 Pro the next day the Pro deepend the color & produced a wetter look. As for topping the Z2 Pro with Z5...........check it out & see what happens. It might look great!
I've even started using Z5 as a base for Souveran,Butter Wet Wax & DP Max Wax. ( I can here the Zealots fainting!!) The Z5/BWW combo is killer. 3 coats of Z5 w/Z6 in between layers, top the final layer with Z8, then the BWW. I QD it with a 50/50 mixture of Carnauba Spritz & Crytsal Mist.
I didn't want to hijack this thread......sorry......but I did want to share a little info with ya!