Unless you are trying to tune a 2 oz trigger or something Jo, I highly doubt the added recoil from the 6.8 is going to be a factor.
You have to factor in most of that recoil is going to be handled by the buffer and spring, it's not like the bolt will be hammering back on the poor lonely trigger group all by itself.
For a long range shooter, I would definitely go with the RRA 2 Stage. It's a sweet trigger and it shoots like a dream.
Going with a really pricey one like a Gisielle or something crazy like one of Dave Lauck's customs is going to give you bragging rights, but it's probably going to shoot about 10% better for 3 times the price.
I hope you plan on posting some pictures and details of the build.