Unless you can find a test pilot to do some plug chops and other tests for you, you are wasting time.
Having said that, yes, you can be lean at low rpm and rich on top.
A moped carb has no means for providing extra fuel when you snatch the throttle open. You open the carb completely at low rpm, which reduces the vacuum at the needle or atomizer jet, which leans out the mixture. The simplest solution to this problem is to roll on the throttle as the rpms rise. If you are still leaning out when you do this, you need to raise your needle, if you have one, and/or increase the size of your idle jet, if you have one and/or enrich the idle mixture, if you have a mixture screw. You can also get a slide with less cut away but we won't go there.
Before you do any of those things, you have to make sure you have a good, clean air filter, a guaranteed clean carb with no passageways restricted, then do a high speed plug chop. This will allow you to select the correct size main jet. Without the correct main jet, all the other adjustments are meaningless.
The main jet controlls maximum fuel flow, consequently, the slower your engine is turning, the less the effect of the main jet, but it does have an effect down to fairly small throttle openings so get it right then try the low speed stuff.
Good luck on the leg.