I'm thinking the high idle is starting to pull advance . Check your timing at idle. Should be rock steady. If mark jumps around make sure your advance springs aren't stretched or too weak .
And putting your hand over carb and idle increases is an indication of a vacuum leak. Could be a leak on the bottom of the intake runner to head port. WD won't find that.
Advance was either plugged or T-ed off when tuning. I'm sure distributor advance wasn't contributing. If the problem is vacuum related, it's either internal in the carb or under manifold which I'll pull as a last resort.