Old school, " arich idle mixture is much less likely to lean out on tip in"
open the mixtures 1/4 maybe even 1/2 turn and see if it fixes anything.
The # 35 squirter may not work any better without the 50cc pump and cam to supply it.
Your idle mixtures should actually be tuned to max vacuum hot, idling, with a vacuum gauge.
Shorty has a good point about MSDs, they "make" an engine more tolerant to transient "lean/rich" events with the multi spark capability lighting marginal mixtures reliably, as well as more spark energy to the plug than a lot of ignitions out there.
Power valve is worth looking at, and should be selected at a rating of 2" of vacuum below your best hot idle achievable vacuum.(you get 9,you buy and install a #70)so it stays shut above 7" and opens quickly to ease transition from isle circuit to power as soon as you hit the throttle and vac drops below 7. Hope this helps.Case