Update
I live at 4500 ft and finally went ahead and soldered up the main jet and redrilled with a #74 bit. this was about 2 sizes smaller than original. The WOT is perfect, 2 strokes mostly, fades to a 4 stroke as the load is lighter. I moved the clip all the way up and this greatly improved the midrange too. Needle had almost no effect before since the main was just way too rich. (plug was black BTW) I also added the very small hole from the bowl to the forward center edge of the slide to act as an idle circuit, another improvement. I also did a exhaust mod, I removed the end cap, cut the outter large tube and then modified the core hole arrangment. I removed the baffle plates, and drilled more holes further up the core tube, I welded up the holes that are near the bottom end but left the small gap at the end plug where the cap bolts on to prevent gunk from pileing up inside. I then rewelded the outter tube back in place. I cut the small tube flush with the inside of the cap and using the left over piece, I drilled a second "small" pipe hole next to the original, welded in and cut flush too. I then inserted a copper pot scrubber mesh and capped it at the end with 1/8 metal hardware wire to prevent the scrubber stuff frome being blown out over time. I then put the cap back on. It's quieter than original and keeps the catalyst piece functional and flows better.
