Thermoquad

First, make sure the secondary air bleed is 0.039-0.040" [ some were around 029, but every 6000 series I have measured is 040 ]. This is the brass tube that runs up the centre of the MJ. The pinched end pokes through the air horn. This pinched section is what you check/drill.

I would start with 0.137" sec jet. Changing the wide open position of the AV also affects rich/lean. I would set the AV at 29/64" & wind the spring to 2 turns, as starting points.