Does your agency already issue Glocks? If so, I kinda agree with @BehindBlueI's that hitting the easy button on this is a no brainer. Now that the Acro-Footprint Glock 45 is available to agencies (or will be shortly), it's even more of a go-to for Glock agencies. And I'm not even a Glock guy.
As for a T&E process or form for you guys, i'm sorry I can't offer anything there. I just don't think you could get any useful data from that little ammo with that small a test group. If you were able to spread that out to a cross section of shooters, say 100 rounds each, and have them shoot some challenging, measurable exercises that included manipulation skills, then you might get more useful data. And have the shooters also rate their impressions on things like ergonomics and compare it to the shoot results.
I know you're not calling the shots, and believe me I feel your pain. Everybody and their uncle is gonna have an opinion, and will tell you why you're wrong. Or maybe tell everybody else behind your back why you're wrong. I am so glad not to be dealing with that crap anymore, and to only be picking guns and holsters for myself.