I've seen both, and based on putting even larger "Berkut" sized canopies on Long EZs, I think we can say that the Long EZ plexi is flexible enough you can make it work in a Varieze frame - the biggest difference is that the Varieze canopy is quite a bit more pointed than Long EZ. There is nothing in the canopy frame that won't let you cut more of it back to fit the larger Long EZ canopy. And the Long EZ canopy can be cut down so that it melds in with the turtle deck...
I presume you know about putting a coat of rubber on the canopy to protect it...it is in the plans...
Beagle