Not that hard to simply follow the part teardown and adjustment that usually comes with a good carb rebuild kit. If that done and the thing still not running right then pretty obvious you have a plugup somewhere where it cannot be seen, it can be in fifty places depending on which carb and design. Some of those plugs can be like concrete and no amount of non-invasive low impact cleaning will clear them out. Ethanol laced fuel has only made that worse.
Very helpful to understand the ranges of different circuits and what they do, i.e., idle, cruising or light throttle and main system for max power, that can point you much closer to where the stopup has to be.
Don't feel out of the loop, you have indeed gone further as most ever want to. They frustrate real quick when the first real serious effort does not result in perfect running.
I emphasize using stock carb for one reason, the OEM will already be dialed in with all metering as good as any on the planet, the factory spent millions of dollars doing it. When you go for different carb you have appointed yourself the carb engineer because now YOU must sort all that out yourself and some of it is not sortable by the average guy on the street unless you already have a perfect running example by someone else who has sweated blood to get there. All that crap about 'it runs perfect' is mostly blather or self-inflating BS, I've found most have not a clue as to what a truly excellent running carb is like at all. Just being able to get on it and feeling 'all that 'power' means you have only done maybe 1/3 of the true work there, most will not sort out light load cruise whatsoever because they do not know how to do it. Ergo, the mileage is not up to par or the complaint 'it needs new plugs', the mark of that. And drilling holes in the carb to get what you need? They are unable to go there. I've done it for 30 years.
People get all these bright ideas about switching carbs from every imaginable source to put on other things, maybe 1/10 of that actually works out to be better than OEM, I used to show customer after customer that over and over again back in the days at the garage. The replacement carb is more often picked because it just happened to be available rather than by using any logic of whether it would truly work right or not.
Here's the thing and most certainly no insult intended or implied here.......... .............. ...if one cannot get a dead stock carb on its' intended engine either running 100% correct or if not, then know the most definite reason why it won't then they will be ill equipped to be jumping into metering a brand new application that never has worked there before, unless like said before, they have a crystal clear example of someone who has been there before. The reality of the thing.
And yes, I have swapped more carbs than you can shake a stick at, some worked great, others were a disaster. Lots more to it than simply picking a size that works on other engines of same size and tune, every engine has different 'gulp' characteristic s to demand worlds of difference in all those little bitty bleed holes that most do not even see as doing anything there. Nay nay good brother not so............ .............. ............
Take the average Rochester Quadrajet carb as used by GM in 500 applications. There were maybe literally that many jetting and other metering changes in every single one to tailor it to the specific engine it was used on, the aftermarket especially now that no one uses carbs anymore has knocked down those 500 carbs to at first maybe 200 and now with no sales probably 30 or so. You go and buy a supposedly 'exact' replacement carb that works on YOUR car engine now and what you get is a mishmash of parts that by far will not work as well as the original carb did. I certainly took back enough crap running carbs on warranty when at the parts store to verify that but knew it all along, why we preached at the garage, 'DON'T buy new, REBUILD it!'. Yes, cost was higher due to more work but virtually no trouble with comebacks at all there doing it. Changing the carb much more often resulted in customer complaints.