On the one hand, I'm seeing Heritage results, and they get a lot of money for things that are really worth nothing. So there is that. Emovie doesn't seem to get as much. I could be wrong, but that's what I see. On the other hand. Heritage charges 40% on each items they sell (20% for the buyer and 20% for the seller) which is absolutely outrageous to me. Emovie charges half of that. So there is that too.
So I really don't know who to suggest. I've had excellent relationships with both Bruce and Grey, which would probably influence me one way or the other, but really doesn't.
I would suggest to you that everything is negotiable, and that would include your fee with Heritage (and possibly Bruce). I'm not even certain that the percentage you quote for seller is correct anyways.
I'm sure you have an excellent system for separating your higher dollar posters (I think we even talked about this once, but I don't remember the details). Most likely the best items will do better with Heritage, regardless of fee.
You probably can't go wrong with giving Bruce a large percentage of your lower value items, things where Heritage's wacky $29 premium would drastically affect the bid price (let's be real, no one bidding on, say, a Forbidden Planet 1-sheet is that worried about the $29 premium).
No one auction house gets the very best prices every single time, but when dealing with the creme of the crop Heritage consistently hits more home runs than they do singles.
The great thing is, both have excellent systems for keeping track of inventory and moving items along in their system, and both pay on time every time.
Hope your wife doesn't have to worry about it for a long time though