Nice, I imagine a reasonable middle of the road strap on (for general home use would have a strong enough strap to hold it to the dyno, but good to hear you are also over thinking that.
Mario rosi daytona head is also NASA spec? Just trying to keep up.
Can you share the maths for calculating what the exhaust will sound like?
If you buy a car with issues I would expect you know what you are doing, not just randomly unplugging things.
Fuel pressure gauge, don't guess.
wideband, don't guess
Timing light, don't guess.
Diameter of line would mean nothing, a massive air leak will cause high idle.
A rattly pcv valve doesn't sound right. Block it off and see hat happens.
Your description of what you did isn't exactly useful.