1) after your thug, I think an X300 is a great way to add weight in the right place and not introduce unintended effects that can come with a RSA change. I am ambivalent about the tungsten guide rod, but if I got one, I would go 15 pounds on the spring.
2) I think the Holosun is a better gaming optic than a RMR, as it is taller vertically, and gives you reticle choices for adverse light. Single dot for most situations, circle or circle dot for low light. Lots of reticle draws your focus from the target, which is undesirable for most lighting.
3) you might wanted an extended mag release. I like this one:
https://www.tyrantcnc.com/gen4-gen5-...e-release.html
4) I would be careful with heavy weighted base pads with a Glock, as they can cause accelerated wear and fall out.most people use the Taran 140 extensions.