Profiling after varnishing is definitely the right way to go if you plan on varnishing the final prints. Otherwise you'll get over saturated colors and plugged up shadow detail. FWIW, I make my own canvas profiles with and without the varnish so that I have option of making prints and not varnishing them. It's fun to compare the differences of the two profiles but thus-far I've always varnished my prints because, obviously the quality and durability is so much better that way.