I only run Tubbs flat wire in all of my ARs and H3 buffers. The AR10s are carbines and have adjustable gas blocks so that helps too. I would use the buffer that it came with rifle came with.
A rifle length 308 buffer and rifle buffer spring will work perfectly fine and be 100% reliable. If your goal is tuning it to perfection with super soft recoil and zero brass damage then the ultimate setup is an adjustable gas block with the JP SCS Heavy with the spring pack. I recently replaced all my 308 rifle buffers and spring with JP SCS Heavy setups. While the normal 308 rifle buffer and spring work great and are 100% reliable, the JP SCS allows you to tune the rifle to perfection. After I switched and got the SCS and gas system tuned perfectly for 100% reliability and locking back on last round the brass looks like it was fired in a bolt gun. zero case head damage.