Thanks for the interest guys.
I'm using a 64gig Sandisk Extreme Pro 95mbs 3 UHC 3 class 10. Maybe check for recommended cards on Google.
As for the weight plate I'm using, it's just a 1.25 pound plate I had lying around. Got it off of Amazon a year ago or so. Could be lighter and probably work even better honestly, but this has been working out just fine.
As far as 16x9 fisheye examples using spacers and the digital extender mode, I have yet to film any footage as I've been working on 4:3 projects but here's a screenshot at the skatepark. I will post some footage when I get some. This is ISO3200 no camera light, pretty horrible conditions. As far as I can tell the quality is just a good with the digital extender mode and the fisheye keeps it's width. Vig is def softer though. Probably better at higher apertures, I will test more.