Something is causing that low vacuum at idle. I believe that needs to be addressed before anything else.
Not familiar with how your cam compares to the SD cam. If close, then SD calibrations should be a good starting point, but John (61-63) has set up a lot of these. I would suggest starting with his recommendations, but address that vacuum before doing anything else.
How about the compatability of the Offy manifold to the e-heads?
Jon.
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"Good carburetion is fuelish hot air". 
"The most expensive carburetor is the wrong one given to you by your neighbor".
If you truly believe that "one size fits all" try walking a mile in your spouse's shoes!
Owner of The Carburetor Shop, LLC (of Missouri).
Current caretaker of the remains of Stromberg Caburetor, and custodian of the existing Carter and Kingston carburetor drawings.
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