Man, stuff like this is why I was sooooo glad my builder had a dyno at his shop. I got my engine in a "turn-key status". Broken in, total timing set for best performance, carb tuned.
With all the other variables I have going for me at start up (rebuilt tranny, complete new PS system, new brake system) I was sure glad to cut down on my "things that can go wrong".
Wow I wish I had your builder! I have all the same variables as you do plus I have one of my mono leafs off as I'm replacing them w/multi leaf.