I guess I'm confused ands need to read the OP again. It's rich at cruise and has a tip in issue. How is that fixed with jets or Tslot? That doesn't make sense to me, but I've been wrong more than right. If it stumbles on tip in, it's either like mentioned above that the pump shot is too small or he needs fuel enrichment from the PV sooner.
Or so it seems to me. But I'm wrong. A lot. When he gets it tuned I hope he tells us what fixed it.
After rereading the original post your correct on which part of the carb to work on, it isn't in the transition circuit at 2600 RPM
OP, try the power enrichment circuit first, power valve opening vacuum rating and maybe the power valve enrichment channel size also
