Has anyone finished an outside corner (i.e., one that projects into the room) with RSIC, DD, and GG? I'm particularly concerned with corner bead, as this is usually nailed in place. Can one nail to hat channel? Thanks for any help.

My "pro" used some 2 inch long galvanized nails and just nailed the metal corner bead through the drywall and into the edges of the first layers, It has been there years without a problem.

You could go with the corner bead that glues on as an alternative.

Ditto.

You might consider a couple of things:

Have the ending clips very close to the corner you're referring to. This will alow that corner to handle more impact.

Consider installing a continuous 1x1x8' backer or some such. This might be installed behind the track and pulled in tight with screws.

Lastly, use a commercial corner bead device that you set on the raw corner bead while in place. You pound this device with a hammer and it cuts small sharp triangles in the steel, driving them and securing them into the drywall. This would be my preferred route, I think.

I had to order some special wide corner beading (because of the double 5/8 drywall) for this exact reason. It was plastic and you glued it into place.

Lastly, use a commercial corner bead device that you set on the raw corner bead while in place. You pound this device with a hammer and it cuts small sharp triangles in the steel, driving them and securing them into the drywall. This would be my preferred route, I think.

Just a data point, I bought one of those things and put up a few corners, then I decided to hire a pro and when he finished putting up the rest of the bead he nailed the corners I had already put up and said he had seen too many of them coming loose over time.

Thanks for all the help! I've seen the stuff that's glued on, but all of these sound like good suggestions. I'm probably going to put up the drywall, but then hire out the finishing. I'm afraid to have the drywallers put up the drywall, since GG and the other steps are so weird. I've had a hard time even finding the materials, let alone someone who's done any of this.