RE: trigger guard movement, or rattling on a lower receiver, there are good reasons the movement exists, both from a practical standpoint, and tolerance perspective.
In short, the generous tolerances of the trigger guards, and the space between the trigger guard ears are by design, it isn't a thing to be "fixed."
TDP width for the trigger guard is 0.430 +/- 0.003. Our TGF follows TDP specs and tolerances. The gap between the rear trigger guard ears is 0.438 + 0.008 / -0.000. Given the rather loose tolerances of the space between the trigger guard's rear ears, TGF (or any trigger guard, for that matter) could be just right, or slightly loose. This is normal, the TDP spec width of the trigger guard and that of the lower inside the trigger guard ears all but guarantee an in spec trigger guard will be loose inside the ears.
TDP diameter for the front right ear of the trigger guard is 0.125 +0.003. If the hole is on on the upper side of the tolerance, TGF's set screw can rattle inside. This too, isn't unique to TGF.
We'd like to remind folks that AR15s/M16s are tools, and every part has a tolerance value. It isn't an advantage or useful feature for combat weapons to be so tight that they lose their tolerance for debris, sand, and mud. TDP trigger guards swing down, and they wouldn't be able to do so if any foreign object in its way can stop them from doing so.
We don't play fast and loose, get creative with TDP specs and tolerances. If we made TGF on the wide side (didn't even think about it, but we wouldn't do it anyway because it has problems of its own), we'd risk the TGF being too tight and not fitting Colt, LMT and BCM lower that are true to TDP specs. We design and produce duty grade components for duty/combat weapons, and we adhere to TDP specs and tolerances.