Great job! And welcome to the world of 944 ownership.
I can relate to the spark plug wires thing myself.
My son and I just resucitated a 1988 NA and got it running a couple days ago.
The past day, it's been running really bad and we were both worried that something had gone wrong. Then this afternoon, my son found that I'd installed a bad rotor - one out of my NA that the metal contact was loose - it wiggled. I'd saved it a couple months ago to show him, and had forgotten it. When I put it on, I'd just assumed it was good.
I brought him a new one and he put it on - now the car runs great. Stupid dad!
Questions:
Yeah the clutches on the NA's don't take a lot of pressure to operate. The turbo clutches are quite a lot harder to depress. What you have is probably normal.
The dip in RPM's returning to idle is normal. It's a slight bug in the DME programming on the early cars. All of 'em do it. Not to worry.
Sounds like you're pretty much right on with the belts. Some whine is normal. The balance shaft belt will vibrate around somewhat; it's a fair bit looser than the cam belt when properly tensioned. My favorite thread on belt tensioning:
Clark's Garage Message Board :: View topic - Belt tensioning without the tool
Typically you'll check the belt for proper tension at about 1,200-1,500 miles and retension if necessary.
You're familiar with Clark's Garage and his excellent Garage Shp Manual?
http://www.clarks-garage.com/http://www.clarks-garage.com/
Welcome again!