I had been using the 5" Red arm to attach the EVF, which never really worked very well for me. Today I chanced upon something simpler that works really nicely (assuming you have the side handles).
I took a 1" 1/4-20 screw and put it through the back left handle, through the topmost vertical screw hole. I made that quite tight, so now I have a screw jutting out from the handle. I put two rubber washers onto that screw followed by an aluminum washer, then I screw on the EVF. Once the EVF gets tight, there is just the right amount of friction so that the EVF can be tilted to the desired angle with little effort -- and it stays put exactly where you leave it.
I haven't tried it yet, but it looks to me like the front handle would work nicely as a mounting point for handheld work -- especially since there are four screw holes to choose from on the EVF itself, so there will be a range of choices to control how far back or forward the EVF sits.
Anyway, since the solution involved all of about 30 cents worth of parts, and it works really nicely for me, I thought I'd share.