Quit fighting the linkage. Use a cable and route to the carb. Remember, if the linkage is way out of alignment, rotate the carb 180 and move it to the other side.

What you may run into is that there isn't enough movement to the firewall side. In that case, I shorten the cable end up. I cut the brass solder on so it had 1/2 the length at the cable end. I cut the threads off so there is just about 3/16" thread. I use a snap on ball joint and I cut the thread end of it so it bottoms on the shortened brass adaptor. Then adjust the horn on the carb so the carb is full in the direction of the firewall just prior to all of this bottoming out.

I tried all of the 4 stroke linkages, bent wires, etc and a direct connection is the best. I have used this direct connect it eight different planes over the last three years. That includes engines mounted upright, on their side and 3/4 inverted and I've yet to find a plane that I had to use a bunch of bent wire to make the throttle work. Remember, you don't have to use the same throttle linkage hole in the firewall. You are free to drill another where you need it. The cable linkage will snake around the fuel tank. The photo is of one of my 4*60's with the shortened linkages.

Don