Well I suppose that it is easier to read all the dialogue in one post rather than over time in various posts, but you don't seem to realize that we thrive on helping folks fix things. Now you ticked us off by keeping us in the dark so to speak. What do you think we have all this knowledge base for? All categorized, filed, numbered, and color coded.
The best answer I can give at the moment is in file drawer #14, color blue, PW 'asksomemore' . There may also be a copy in other drawers but they can't be opened presently for the case of covid security and border restrictions.
Enough BS
Hang in there, there will be plenty of suggestions coming your way, this one is super interesting. You have probably missed one dinky little item that needs a half turn adjustment.
Couple of thoughts to get you started:
When you did the carbs, how far did you tear them done, and did you use new gaskets. Did you check out the enrichment vales as well. Are they seated completely and properly in their boots, check them out again now. Did you clean the idle mixture circuit and how did you adjust it back to spec?
Did you check out the stator output. What is your voltage at 5000rpm? Did you check out the grounds, especially the one at the right lower front of the engine? Are the battery terminals clean and tight, also check the terminal to cable connection.
Check the fuel line from the pump to the carbs, is there a kink there somewhere. 3psi is not a lot of pressure, but it is spec and should work just fine.
Seems like you have or gained a lot of knowledge in your process, Good for you!!! Trouble is, now that you have posted this, it becomes a challenge to some of us, and now you can't get rid of said unit until we get the issue solved or we'll be around to haunt you for decades.