Anyone know what the torque requirement is to activate the YHM crush washer?

is there something specific you need to know the torque value for?  Most just twist till the phantom is timed to your liking ...job done.

Just hand tighten the muzzle device, then crank over until the timing ligned up. Making sure to rotate at least a half turn.

Barrel vise highly recommended. It takes a bit of force to initially start the crush washer to give but once it goes its easy (provided the barrel is locked up properly...)

This is going on a brand new Krieger barrel and to be honest - I don't have any desire to torque the living H E double-L out of the thing and potentially degrade accuracy.

Quoted: Just hand tighten the muzzle device, then crank over until the timing ligned up. Making sure to rotate at least a half turn. Barrel vise highly recommended. It takes a bit of force to initially start the crush washer to give but once it goes its easy (provided the barrel is locked up properly...)

I would recommend receiver blocks.  Sometimes your barrel nut/comp/whatever might have been installed too tightly and with the barrel blocks you end up spinning the barrel and leaving a big aluminum smear around it.
The -23 indicates the torque for peel washers is 15-20 pounds.  There is no value given for the crush washer and it specifically says that the washer does not require torquing.  It does indicate the comp shoud be hand tightened then use the wrench to time the comp by rotating a minimum of 90 degrees but not more than 460.
As I remember from your previous post on concern for overtorque I would use the crush washer and try to get it timed as per the -23.  If you see that it is going to take more than about 180 degrees to get it timed it might be a good idea to precrush the washer to prevent putting too much stress on the muzzle.  Do it slowly with several trial fits so that you don't make it too small.

For an accuracy oriented barrel, I always recommend a vortex.  Why?  Because all you have to do is hand tighten it.  It is self-tightening.

I usually just put a dab of blue loctite on mine, grip em as hard as I can with my hand, and twist them as best I can.  Done and done, no worries about crush washers or any of that BS.

If the muzzle is threaded right and the comp is installed right, a standard A2 or whatever won't have a negative effect.  The Vortex pretty much eliminates any chance for negative effects due to overtorque.  I haven't had any probs with A2s and Phantoms on accuracy rigs.

Quoted: This is going on a brand new Krieger barrel and to be honest - I don't have any desire to torque the living H E double-L out of the thing and potentially degrade accuracy.

Then do what the Army highpower team does: use peel washers to time it and locktite to secure it.  Blue should be fine if you hand tighten it.

Seen a lot of highpower, CMP rifles with no muzzel device at all. Due to the ban the rules were changed.

If the rifle is just going to be a match rifle, I would of left the muzzel clean, then there is no chance of over crushing a crush washer.