Warren in Lancaster, PA
I do agree with you, Brian, the idea that aids, jigs or gizmos, are going to help is more power tool thinking than hand tool thinking. The time saving from hand work is that you mark a line, you saw to the line and the joint is done. There is no messing around with trial cuts before sawing or cleaning up after sawing.
If you really want to speed things along with production work here are some hints from 200 years ago:
Make a dedicated mortise gauge for an individual mortise chisel. That way you save set up time and the inaccuracy that comes with each set up. If you find that when sawing to the line your tenons tend to be a little fat, or a little loose, you can make a slight adjustment to the gauge that will be there the next time you use that chisel.
Use a tenon saw for the shoulders, cutting right on the line. Use a rip saw for the cheeks, again cutting right on the line.
Making a large number of tenons is a chance to improve skills. If a large number sends you to the machinery, you can manage to avoid skills.