We played expert on this earlier with the MvM Potato/Iron Gauntlet group. Really good map, actually. Great, easy-to-learn layout. Had a lot of fun jumping around various areas as scout.
The expert waves felt pretty good to me, though bear in mind I don't have a ton of MvM experience. Maybe the arrival of the tanks in the last wave could be spaced out just a touch, but I'll leave those sorts of suggestions for Spycrab.
I was concerned the map might be too small to fight off the waves, but that wasn't a problem at all.
Looks like you already addressed the lighting as I don't remember seeing any super bright spotlights. In fact, the whole map looked really great. So overall I don't have much feedback other than "great job!"