Where to start

Since your engine has the head off, you can check things and know where you stand. You have checked Deck Height. I would now find TDC and mark that on your Vibration Damper. They can be way off. The most important thing with any engine is the valve job. The most important thing about a valve job is to seal the valve to the seat, and keep the seat as high as possible, period. It does not matter what equipment or how many angles were used. Check them by Lapping a couple valves at random, intake and exhaust, on both heads. CC your chamber(s) then calculate Compression Ratio. The simple ratio, not measuring volume, not all the nits, you are not a Class Racer. If you want mill the head, you can mill up to .090 of an inch on a slant 6. Maybe check that, since yours is that new... Then call your Cam Company and tell them whatever they ask for. Do a bowl blend, Match the intake and exhaust ports to the gaskets if you want, cc and equalize the chambers if you want. You will love how your slant runs.