Dot-to-dot doesn't matter. A degree wheel needs to be setup and the timing events checked to the cam card. Your cam has a LSA of 110 and an installed 'centerline' of 106, which should be 4 degrees advanced. Some places grind in that advance, some do not. It should be possible to pull a valve cover and use an indicator on the valve stem or pushrod or rocker to get an idea of where your centerline is currently. It's best to do it at the lifter, but with the engine assembled that's a bit tricky, so do what you can. Your engine guy should be capable of doing this for you as a double check too.
If you did this when the engine was built, describe how you did it and the folks here should be able to tell you whether there's a chance for error or not.
Also, don't feel like you wasted $800. How much more would it cost if you'd gotten the car on the road only to find you hate it? At least you know ahead of time, and it 'only' cost you $800 vs a bunch of exhaust gaskets, fluids, and time to R&R the motor. Depending on how you value your time, that $800 might be considered cheap. I would certainly consider it a cheap reassurance.
As far as the rich condition - swapping the carb may help, but tuning it is likely the better route. That said, trying a carb your engine guy suggests (especially if he has one on the shelf to 'borrow' for the pull) might help show how well the engine SHOULD run if it was tuned right with almost any carb and if those numbers are closer to your expectations then you'll have your answer.