Noveske 300BLK Uppers: 8" or 10"?

[Eurodriver]

I'm set on a Noveske because I've seen my buddy's 14.5" 300BLK Lo Pro and its an incredible piece plus BCM doesn't make any and I don't like AAC's handguard.

I can't really decide on barrel length and I'm concerned about why Noveske chose stainless steel 4150CMV chrome lined. Even though this weapon won't see as high of a round count as my 5.56s there's still that old school mentality of "Stainless steel is for slow fire precision." Is that an issue with the 300BLK?

I have a 10.3" AR15 with an AAC M4-2000 and the 300 BLK will wear an AAC 762SD (mailing the paperwork off next week after buying it two months ago...I could be 1/3 of the way through the process by now). The SD is about 2" longer than the M4-2000 and 2 ounces heavier. I wonder if using an 8" barrel will offset both the length and weight differences between the two?

My main concern is maximum range. I know with subsonics I shouldn't even think about distance but with supersonic 300BLK out of an 8" barrel, what is the trajectory like if zero'd at 200 yards from the muzzle out to 300 yards? Am I going to have to aim high up close, super low at 100 yards, dead on at 200, and then high as hell at 300?

My other concern is rail length. The 8" barrel comes with a 7" rail which is less than ideal. The 10" barrel comes with a 9" rail which would be identical to my SBR.