Ok, so I'm looking at building myself a fixed A2 carry handle dissipator and am not entirely sure how to sight it with RIBZ.
I have a 20" and 14.5" removable CH setup for RIBZ and am a fan, so I would want to do that with a dissipator build. My only problem is I'm not sure if I would using the Carbine or the Rifle method for zero and adjustments.
I've always used this article as my reference, which has been great, but doesn't really touch on my needs for this one. https://savannaharsenal.com/2017/04/08/how-to-zero-ar-15-a2-type-sights/

As always, and help would be greatly appreciated.

The method depends on whether you are using a 6/3 rear drum or 8/3 drum.  Fixed carry handle should be a 8/3 drum, so I guess that’s ‘rifle method’.  

With shorter barrel your sighting shifts from velocity loss will occur at longer ranges. So your 600 setting could turn out 600 marking plus N clicks. You can offset that somewhat by small best fit to your 100 yard zero (maybe shifting centroid of group up one click on front sight).  The coarseness of the front sight is the limiting factor. 1.25 MOA for rifle length sights, courser for everything shorter. So at 100 yards you could go from a centroid just below zero, to just above, and not get perfect elevation. Usually a little high at 100 fits best.

I’d zero the modified 100 drum setting ( that’s 3-setting minus 3 clicks with an 8/3-drum) at 100 yard black target using a 6 o:clock pumpkin on fence post hold to get group right at 6 o:clock in the black.

8 shot groups are easy to find center of group graphically if you don’t have a phone app to do it. You find the midpoint of 4 pairs then use those 4 midpoints as two pairs to get two more midpoints. The centroid is then half way between those last two balanced midpoints.

With an app a 10 shot group is better. 100 yards is good for seeing group even with a cheaper spotting scope. Long enough to fine tune windage but not have too much cross wind impact.  Once the 100 setting is zeroed to the courseness of your front sight you can check the 50/200-ish drum setting for elevation (maybe fine tune windage at 200 on calm day), but likely won’t need to make any changes for military-scale targets.

Thanks, I think can make that work.