Forget about vacuum advance until everything else is happy. I seriously don’t any big lock will be happy with 34 total unless it is a B1 head or better. 38 is more likely the least it should have and may go as high as 42 unless there are other issues.
I don’t know about your converter (love that cam BTW) but you’ll need at least 20 initial (base) and that means it can NOT drop below 20 degrees when it goes into gear. That’s at a minimum.
I don’t know what you have for an ignition system, but it needs to gain advance all the way to peak torque and at that point it should continue to add advance to max RPM.
The total timing will be affected by how much retard the box has with RPM.
Once you have that part sorted out, you can work with the vacuum advance. You will probably be able to add 10-15 degrees of advance with it but when it comes in will be critical.
You may also be able to (MAYBE) use manifold vacuum instead of ported (timed) to pull the advance a bit quicker, like idle and above but you just have to test for that.
