sorry, must have missed this post last night.
don't really have a guide, it's as simple as stuffing a tiny o-ring under the hop adjustment wheel to give it a bit of friction.
certainly if you're wanting to push it to the point of short-stroking.
the ak build i mentioned earlier was a 455mm barrel but it wasn't short-stroked.
generally i tend to go with just don't change the barrel length so you don't have to start messing around with voluming, although it's perfectly plausible to run a shorter barrel than the outer to enable short-stroking.