I would try a different plug, like an Enya 3 to help with the idle. The other problem you might be having is that the motor still has not fully seated yet as evidenced by the good compression. Enya machines their motors to last a long time and sometimes can mean a longer than normal break in time.

Try the Enya 3 plug and close off the hole (rich) a little and see if that helps and let me know. IF it runs wide open clean for an extended peroid of time, chances are it is not the carb.

Thanks
jeff G