8.5 is on the short side, go 10.5-12 if on a budget and are going to have this be a go-to rifle.
A $209 psa 10.5/11.5 freedom stainless/nitride upper with fsb shaved into lopro block and an added alg rail wouldn't be much more than 300. Or he could keep the fsb and throw on magpul Moe SL handguard for $30 and not have to buy a front sight.
That would be about 230-240 for upper with pinned front sight block and SL
A 209+100 psa/alg upper needs the cowitness 12'o'clock m-lok rail section ($20?) plus a front sight (mbus is the least expensive one worth buying, about another $30. So that would be about $360 for upper, emr v1, mbus front signt.
So if I were on a particular budget, I'd be choosing between:
-$240 for upper with fsb and moe-sl handguard
and
-$360 for upper with alg emr v1 and mbus sight.
Option #1 affords you the difference of the cost of an upgraded trigger like an MBT or perhaps Geissele if on sale. I'd be more accurate with the non-free float and sweet trigger than free float and milspec trigger. There is also the option of "get both."
Andro Corp should be able to put together something that appeals to you as well. They sell a 10.5 that includes bcg, ch and FF rail for 435. If you could get them to swap out for an ALG rail, that would be nice. Or maybe their house-brand rail is good enought?
So it all depends how you want to allocate money and how hard your ceiling is.
I don't think you can go wrong either way. I'd probably ean towards a FSB and Moe-sl and MBT/G2S for $350 over a milspec trigger and mbus for $350, if I had a hard ceiling. But you can always add stuff like triggers down the line. I just got a emr v2 13" and it's suhhhhweet. More expensive than v1, but doesn't need a 12'o'clock rail section for front sight.