some 2K epoxy primer then black base coat. 400G wet paper is used before the base and usually I've found scuffing the base isn't required as long as it's soon after it has flashed not days. If you plan on working on this for awhile you may want to use that intercoat because the basecoat will break down if it isn't cleared within the time alotted on the specs. You can buy intercoat which is kinda pricey or you can use a thin coat of clear. When you buy the eurethane clear you'll prolly get enough to do half a dozen or more tanks so I'd just use that for a intercoat. Generally speaking, anytime you put down a 'different paint' layer you should rough it up with some 400-600G wet paper to give it tooth for the next layer. Which then brings up the wax remover. Wipe the crap out of it before you lay down any paint. Don't know where you're from but I found a gallon of wax remover/degreaser from Napa auto for around $15 and it comes in handy for everything especially cleaning off panels and lasts a long time and won't hurt the paint as long as your gentle.
+1 on the wicked, love it, only thing is if you get carried away and paint too fast the Wicked doesn't flash quickly like solvents and you start streaking. Patience, smoke breaks, and a heat gun help
have fun! want to see some pics