The Mustang makeover horses (for the adult division, anyway) that get through to the competition are usually going under saddle, to the level they can do a simple “ranch horse” type pattern (WTC, turn, stop) and trail course (gates, trot poles, back, side pass, bridge, etc.). Every now and then one will be taken through in-hand, but most trainers that don’t find themselves with “100 day horses” drop out of the competition. The really experienced trainers that get particularly “easy” horses will do a lot more, although usually Western type things like working calves or roping. Many have a fair bit of trail miles. If your client isn’t familiar with the idea, they can watch “Wild Horse, Wild Ride,” or look up the EMM Facebook Groups and YouTube videos.
Definitely not an option for everybody, and may not be likely to find one straight from a Makeover depending on location, but something to think about. May be more of an option for somebody else reading the thread looking for ideas of where to horse hunt.