Well, after a month and half, countless hours under the hood/scratching my head, consulting with backyard mechanics and licensed mechanics alike, I flushed the fuel system, swapped fuel filters a hundred times, did a full tune up including solenoid, plugs, wires, cap, rotor, replaced most vacuum lines/components, swapped the fuel pump, swapped the carb for a used, cleaner one (I have a parts machine I was able to pull parts from for a lot of these swaps)... None of this made a difference! It still ran real "sputterie" after it warmed up.
After all that, in a last ditch effort/curiosity I removed the thermostat,.... Presto! Runs great!,. Temp gauge now shows lower than normal instead of mid range on temp., can heater, isn't as warm,,.. But!,.. It runs normal! Zuki carbs must have a temp. Controlled choke adjustment that didn't like running too warm...