Need Help. Putting together my first A-R, Need oponions and suggestions

[TexA-R]

The rifle is going to be primarily used for hunting and target shooting. I want to use the best possible parts I can while staying reasonable. I almost have the lower complete. This is everything I have and plan on getting.

•MEGA ARMS MATEN billet ambi recievers

•Geisselle SSA-E

•V7 weapon systems ambi 57° safety selector

•Hogue overmolded grip w/ beavertail

Ordering soon:

•Magpul UBR

•Slash's extra heavy buffer and spring

•BAD Titanium Enhanced Pin Set

Plans for Upper Reciever:

•Fulton Armory 18.5" match barrel (not certain on which one, medium weight vs. Light weight chrome lined)

•Fulton Armory Matched NiB BCM

•SLR Rifleworks Adjustable Gas Block

•15" Free Float hand guard (not certain on which one yet, I need to decide which barrel first)

•Jake Brake Muzzle Brake

I really need to figure out which barrel I need and that will be the last thing I need to figure out. Any help would be much appreciated. Thank you.