If you switch to Canon or Nikon, you will have wider selection of lenses from both Canon/Nikon and third-party makers like Sigma. Plus, you can use the same lenses for when you switch to a dSLR, if at all. OR, you can experiment with the larger forma...
I use a Toyo-view for ground glass and film viewing, but it is just under your range at 3.6x. I appreciate the simple slim design because I need to view through a fold-out hood, but I do wish for a little more power.
Ahh. Nooo. Go with Toyo... Im getting new tires for my car and Im getting toyos they are probably the best tires out there. They have better treads then all of the other tires which keeps you safter and gives you better traction,... for 215s... depen...