centrifugal advance curve MSD Distributor

The proper way to set the distributor up is to find the initial timing your motor wants first. The way to do this is to start with the factory initial timing setting and continue to add timing in 1 or 2 degree increments while keeping the idle speed the same (that is readjust the idel speed after each change in timing) until you obtain peak manifold vacuum. You may wind up with 20 degrees or more and if the engine wants to kick back against the starter when starting you will need compromise on the ideal setting and back off the timing until it doesn't unless you want to install a timing retard for starting.

Once you have established the initial pick the stop that the sum of the timing stop and initial adds up to 35-36 degrees.

No vacuum advance on that distributor so no work there. To do any better than that will require many trips to the track or time on a dyno.

I noticed you say you are using an 850 double pumper. That is way to much carb for anything but a very hot race only small block and will be real tuff to dial in for decent street manners. Based on your specs a 650 double pumper would be more appropriate or a vacuum secondary around 700 cfm.