When first starting an unknown build, the choke lever can be your friend. once the bike has warmed up on the stand you can get an idea of your present rich/lean condition by slowly squeezing in the lever.. If the Rpms start to drop as soon as you move the lever in a tiny bit and the bike is on the verge of dying at 3/4 in then you should be safe to continue with other testing.
Then grab the thottle and twist it to about halfway and repeat the choke pull test. You should get about the same results.
If you do the half throttle chole test and you dont have a significant drop in RPM or rich blubbering at 3/4 choke pull or you cant kill the bike with full choke at half throttle then you are probably jetted way too lean or small.
This is just a poor mans ball park methed of finding a staring point