Suggestions for a new AR upper build

Hi…I’m new to the group…My name is Chris Brosnahan, I’m 58 and live in Lake Worth, Fl.I own a 16" carbine built on a PMC lower…I’m planning on replacing the barrel on my upper with a threaded “pre-Ban” M4gery style…I want a three rail gas block and a REAL flash hider ( my current one is a machined-on, faux post-ban hider) My questions are: 1) Who has the most reasonable 16" M4gery style fast twist 1 in 8 or 7 barrel??? I can live with a 1 in 9, but would prefer the former. 2) Steel or Aluminum gas block - is there that big a difference??? 3) Flash hider - which is better, The Vortex or Phantom??? 4) Best (and most economical) BUIS front sight??? I’ll be doin’ all my own work - I’ve got all the tools except for the Brownells Front sight bench block and a barrel vise adaptor…and a large bench vise (easily taken care of at Homey D’s). I reload and have been doing so since I was discharged from the Army in July of '74.:confused:

I’ve been doing research on line - the least expensive barrel I’ve found is available thru Bushmaster ( around $220 delivered, but it’s 1 in 9) I want the faster twist for heavier bullets, i.e. heavier than 62 grains…i know Eddie from Gunsmoke Enterprises in Okeechobee and he has nothing faster than 1 in 9, so I might hafta be satisfied with that twist…I’ll most likely be buyin’ from Brownells or Midway as my 03 C&R license gives me dealer discounts…Feel free to e-mail me directly at chrisbroz@yahoo.com.