My 2x6 had a flip cap which worked well, 2 cables, pull one it opens, pull the other it closed.
My current 3x8 flip cap, not so. The operating arm that flips is welded wrong. Rather than try to cut it off and get the arm right, I just use 2 cables. The first holds the flip cap from opening too far, before I set that the cap would tilt so the cap hung straight down, then there was only one way to close it, I had to climb a ladder and flip it. After 1 day of that I attached cable #1 to hold the cap at just short of flipping over, it is attached to a fixed point on the arch. The second cable (each is light weight SS cable) has a hook on the end, to open the cap I pull until cable one stops it, then I hook #2 to a chain at the back of the arch. This works well thus I won't likely ever change the position of the operating lever. My first one had a stop welded to the mounting bracket, the current one does not. Both just run thru a small hole in the steel ridge cap. If memory serves me, I think those holes are about 1/8" (made by driving an 8 penny nail thru the steel ridge cap) and I think the SS cable was 5/64' This has worked well for about 12 or 13 seasons.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.