20" Barrel & Bolt Questions

[Will_Power]

Hello all,

I've been lurking around here for quite a while trying to soak up knowledge while I finalize my first AR's part list. I'm a might bit stumped regarding my barrel and bolt choice.

I am putting together a 20" SDM-R/A4/SPR-inspired setup. Mostly to train my own marksmanship abilities out as far as I'm able to, but also with a consideration towards possible hunting and second amendment contingencies.

I'm on a bit of a budget, and do to my own lack of skill, a high-end ultra match grade barrel is going to be something I can't take advantage of (I'll assemble the basics, first, and then save up for a Gisselle trigger and suitable piece of glass in the 2.5x10 range, and then consider a barrel upgrade).

That said, what should I be considering for a barrel (and bolt)?

1. Matched/headspaced bolt? How important is this? Compass Lake has a matched bolt and barrel.
2. Barrel profile? Is there a difference between the Govt. Profile and a "medium" profile? For my uses which is going to be a better bet?
3. 1:7 or 1:8? I'll be shooting the heavier bullets. Is the 1:7 going to make that much of a difference or is it practically a wash?
4. M4 ramps? They important with rifle gas?
5. Wylde vs. match chamber? Seems the Wylde chambers are the best bet out there, right?
6. Chromed barrels increase the life of the barrel, but decrease accuracy, so I've heard. That something I need to worry about? I like finding any way to ease my maintenance and upkeep burden.

Along with the questions, are there any standout barrels in the low-mid price ranges? Preferably in stainless, too, as I live on the wet side of the Cascades.

Thanks for any insight you can toss my way.

TL;DR? Looking to build a SDM-R/A4/SPR type setup. Is there a 20", 1:7 or 1:8, Wylde chambered barrel in either Government or medium profile? Does it also happen to come in stainless?