Apparently all "polymer" guns are the same. I forgot. So using that logic you should also limit yourself to only one handgun with a metal frame as well. Presumably they are all the same too.
Look, I'm just saying he's trying to catch every possible category of gun for this new shooter and my personal opinion is that can be distracting as it's too much information to process at once.
('Sides, if he doesn't bring out a Desert Eagle and a tip-barrel Beretta .25 ACP, then he's really not covering the whole field, right?
)
Is a Glock
just like an M&P? Or xD, or even that Taurus one? Of course not. But if you're showing him broad categories, then yes, having either one of those covers polymer-framed striker-fired autos.
Letting him shoot a single-stack SA 1911, a striker-fired polymer gun, a DA/SA auto with de-cocker, a DA revolver, maybe the little Makarov, and a .22 target auto, (maybe go crazy and include a single-action revolver, too) would give him an understanding of the different systems.
From there he could decide the bigger-picture questions: whether he prefers more controls or fewer controls, heavier steel guns or lighter polymer guns, revolvers or autos, etc.
That's probably 200-300 rds of testing right there. Enough for a new shooter on the first day. When he's ready to hit the range again or go off to the gun shop, then he can say what category of gun he liked and can narrow the focus from there. (
"You know, if you kinda liked that Glock, you should test out the M&P and the xD. They work the same way but each has a slightly different feels to it and you might like one of them even more..."
Look, if it's that big a deal, bring the Glock and the M&P. I'm just trying to simplify things for the new shooter who's going to have a lot to process in a little bit of time.