I like 2.66:1 plus it makes longer waterfall and more oval background, but I'd not say no to a 1.33 with no dual focus.. Dual focus is a pain, just getting to play with a Moller 32 now, looks lovely but it's slow. 2x stretch is bonkers, but you can just crop the edges off.
Screw Iscorama's old patent, they should just that method and use the money for the patent case when they clean up. Same goes with Kodak optical reducer patent, I mean those guys are flogging all their stuff, someone needs to buy that patent too.
The SLR magic has OK flares, the Apefoscope ones are just too too much at the moment. There are times when you want a lot of flare as an effect, but those are all over the place and pin sharp, great work on the project so far, kudos for doing it too! those flares need some serious taming in order to be aesthetically balanced though. Also waterfall style oval bokeh is pretty essential to the look of anamorphic, I'd say moreso than the flares, it's what creates the milky depth...