A good place to start is around 16-20 deg initial and no more than 28 total.
Make damn sure you have adequate fuel pressure, do not cheap out here.
And buy a good air/fuel mixture gauge.
Depending on how much boost you are running, a retard for boost may be needed when you surpass around 5 psi.
There, your learning curve just got shorter.
And your wallet just got lighter.........