I'd start from stock, and move it up 2* at a time, checking for pinging and for hard starting due to too much advance. Don't forget, what works now might be something else in the dead of summer.....
“When the going gets weird, the weird turn professional....” ~ Hunter S. Thompson~
R.I.P. Rubberdown. 1971-2012
2005 E.G. Classic
Baisley Oil spring
Rinehart 3.5" pipes
S&S adj pushrods
3 stickers, adding 5 hp each. I swear......