Pampered?
Not near enough info to help you with a prop selection. What was the max RPM at wide open throttle? You want to see about 4400 to 4600 rpm or so on a tach that is verified correct. Older tachs are often not correct.
Choices of prop will be limited as the drive is older. The dia. and pitch should be stamped on the side of the prop. You can get a stock replacement from West Marine (Boats US) although they might have to order one.
I do see its a small block Chevy. I also see it has power steering. On those sea drives you need to be very careful of the large rubber boot mounted to the transom plate. If you can't confirm when it was replaced last...replace it now. A tear in that boot will will sink you fast.
Also do not run with the drive up. These drive use hyd. cylinders under the engine to trim the run angle (if you have that option).
The price you paid seems fair though. Wellcraft is very well respected.