I would use an adjustable gas block way before a pigtail gas tube.
Ultimately it does come down to your gas port size... especially with it that close towards the chamber.
Pressure closer towards the chamber will be the highest... so if you had an oversized gas port ( IF ) then your BCG will be slammed pretty dang hard back..
I'd try a SLR gas block... BUT be sure what ever you use, that you can readily access the adjustment "screw".
An adjustable gas block offers the best ( IMHO ) way to tame the cyclic speed of a Pistol AR's action.
Better then buffers, springs and pigtail gas tubes.... you don't want the added mass of a heavier buffer weight, the added slam from it and a stiffer spring, causing your rifle to dip down after every shot.
I went through all that with my blowback 9mm AR.
Thinking about it... all the adjustable gas block does is restrict the volume of gas flowing into your BCG.
And IMHO.... that is the best way.
This link will show how high the pressures can be... as well as explain it. http://www.ar15barrels.com/prod/operation.shtml