You need to set it as Bosswrench suggested. On a dyno. That is to say, pull the engine out and put it on a dyno. Even so, that's gonna' be off a little because of the dyno headers. They are going to be better then what you can get into the car.
I can tell you what my settings are but unless you are running the same setup, it doesn't really matter.
A vacuum advance can give you a few more mpg at cruising but you need to be plumed for vacuum into a common vacuum plenum, which you are not. Considering the intake that you are using I wouldn't consider putting any holes in it and unfortunately 48ida's don't have any vacuum ports.
I can tell you that I am running 15 degrees initial advance with 35 total. It's idling at about 800rpm. There is a little bit of a contradiction to that in that the aluminum heads not only don't need that much total but they don't even like it. Generally 33 to 34 is as much as they need. The tip in response is much better in the 14-16 degree range. You clearly can feel the difference between that and say 10-12 initial.
Iron heads are different with total advance and your actual compression ratio will affect that.
The contradiction comes in because of the Webers. That set up likes as much advance as the fuel octane will allow. 36 total is about right for them on iron heads.
I found that running on premium pump gas, about as fast an advance the fuel octane can handle is all in by 3,000 engine rpm. You might find 3,200 a little better.
The days of being all in by 2,000 rpm are done and gone unless you want to run on pure 106 leaded racing gas.
Oh and Bosswrench is also right about setting the jetting and the advance together. There are a bunch of settings that will run fine with the Webers all the way down to 125f mains and all the way up to 170f mains but the advance rate changes as do the plug heat ranges so when you do this it's kind of like one of those one man bands playing the drum, a wind instrument and the cymbals between your knees?