Besides the flat steel barrel nut wrench, you should also figure on a barrel vise with the appropriate bushing for your barrel.
I'm another one that has never needed a barrel vise or any vise for that matter. Just have someone hold the barrel tightly and a few LIGHT taps with a hammer on the barrel wrench is all that I've needed.
Other than for about a grand total of $250 and 15min your done. Till the next time, and the next, and the next........