OK, after reading back on some of this, since we are going forward, I will put in my two cents worth.....
STOCK.... I have agree and go with the UBR or PRS, either would be acceptable on such a weapon, but being it is to have two uppers, I think the UBR would be the logical one..
GRIP...Well recently I installed the Hogue overmolded grip on my AR-10 A4 CB, and I have to say that it is a great grip and I think it even helped improved on my accuracy, being it was a more comfortable grip and gave me more stability in handling my weapon.
HANDGUARD...Well being I have the MI drop-in for mine, NO, I am not going to suggest it
, I am going to say that being I have not alot of "hands on" experience with the Free-Float handguards, other than the research, I am going to say The LaRue Tactical Free Float Hand Guard, in my opinion it is one of the best and durable built HGs on the market...
So that is my input,,,,,,,on this subject, what is nest...
BMS