Did the tank on the old z1000 a couple of weeks back with "M.C.S. Premium Fuel Tank Sealant". I bought it through ZPower Australia
http://www.zpower.com.au for about $90 ish. Great parts supplier and really good service. Cant recommend them enough
Easy enough to use and didn't have any dramas. I haven't filled the tank with fuel yet but can't see that there will be any dramas. It seems to get into all the nooks and crannies, just gotta keep rotating the tank while it dries.