just went out and marked the head ports, there is not a lot of material to worry about.
some of the ports are 50% dead on, and the largest ledge is .065".
don't think the risk to reward is quite worth it. i am not too worried about getting the last HP out of it. maybe if i was planning a FI install.
so, i think i am going to install my IM and spacer as is, no head porting.
the spacers were in more need of porting than the heads.