Updates on this?
Also, just to confirm for my own curiosity, you mentioned the floats were set at .375? Is this 3/4 of an inch from the airhorn surface?
If so, your floats are set too low, should be 1/4" to 5/16ths from the airhorn surface measured from the top of the float. The floats set too low will cause a very lean condition like you are experiencing.
Your jet rod combo is a 30 which is plenty rich. What power piston spring are you using? If it's stock, and you said the engine vacuum is 16.5 your spring may be seated too long into the fuel curve causing a lean surge as well
I bought an Edelbrock q-jet pistion spring pack, helped me quite a bit dialing in mine.