Hi guys, I've been doing a lot of research but couldn't find the answers I was looking so I figured I'd give it a shot here:

I have a Huntertown Arms 5.56 Kestrel coming, maybe another 1-2 months on the stamp. Same timeframe for the SBR stamp. IN the meantime I am preparing my SBR build and I have a few questions:

Here's what I got so far:

Registered BCM Lower built by Grant with Geissele SSA, suggested I go with H2 buffer and blue Springco Spring. Question 1: I've heard posts here recommending H3 buffers and green Springco springs? Thoughts?

The upper:
BCM 11.5" upper with DD RIS II handguards
Question 2 : For a dedicated upper, who can do work on the gas port or should I go with a Switchblock? Is stock alright?

Other parts of the rifle include Surefire X300, Aimpoint T-1 / LT660, Larue Handstop and MS3 sling.

I mostly shoot PMC Bronze due to price but will try to buy M193 variants whenever this price surge cools down.

Goal of the rifle: all purpose. Must be ready for home defense, range, classes, etc. I do have a backup 16" BCM/DD rifle but I want this to be as reliable as humanly possible.

Thanks in advance.