Here is the thread with the parts list on one I just put together and very happy with.
https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/11192760/Re:_Bit_by_the_308_bug#Post11192760
Rifle length gas system, 12" rail, gas block un-covered.
Nice write up. Thanks. Seems like you veteran builders go with the rifle length gas.