In my experience as a Colemak typist and heavy vim (or vim-emulation) user, the best solution is to bite the bullet and _not_ remap any of the keys. This is obviously annoying for hjkl navigation at first but you get used to it pretty quickly. Plus there's the added benefit of being able to easily use hjkl for navigation everywhere that uses them but _doesn't_ let you remap, which is a lot of places.
And I can use Vim without trouble on qwerty and on my own custom layout. The only adjustment to the layout I made when designing it was placing hjkl in reasonable positions (e.g. avoid the worst placements, but they're still not on the homerow).