AHA! I knew it! I want an autographed...... dog frisbee!
Time for the initial GG update. I've got all the pieces on the subfloor up, and I have to admit that working with GG is not as bad as I had expected. I thought I would post my process as well as my photo proof of progress in case it will help someone else along the way.
Things you need before you start that you might not think of before you do this the first time:
2 - 5 gal buckets. One filled 3/4 of the way full of water. You can use the empty bucket as temporary storage for your speedloader, and you can use the bucket of water to cycle water in and out of the loader and leave filled if you are going to be away for more than 20 minutes. Even if you don't think you'll need to stop, I'd recommend that bucket of water. You'll need to take a break at some point, and it's easy to have it there so you can store the speed loader easily.
1 - Can of WD40.
This stuff works wonders for cleaning GG of you! You also use it to lubricate the speedloader, but that's a much less impressive use of the stuff

1 - Box of shop towels. Paper towels will also work, or anything you can use to wipe up spills. I would recommend something disposable, though. You don't want to end up just smearing around GG already on your rag.
1- Trash can or box to throw your dirty towels to keep them out of the way and off the floor. You don't want to step on a rag with GG on it and then spend the rest of the day tracking it around.
Here's my process (Some of these come directly from the SIM, others are what I learned along the way):
1) First I arranged all of my stuff. A work area for applying the GG. My GG immediately next to that to limit drips on the floor. My two buckets, WD40, and shop towels next to that.
2) Label the top of your GG bucket with 3 regions (you don't actually have to label it, just remember where not to touch; but it serves for this example). The first is an area you don't want to touch. This gives you a place to wipe the loader nozzle on the bucket lip. The GG will get on the lid's seal the next time you close the bucket, and if you grab that area when you open the top.... well, refer to the WD40 note above. The other two areas are where you can seal the bucket temporarily between uses. This keeps it from drying out, but still easy to open the next time.

3) Since I was doing my subfloor, I laid out 32 - 48 s.f. of drywall. That's 2-3 loads of GG, and that's about what I could hang in 20 minutes. I laid them out and pressed them tight against each other to limit drips on the floor. Below you can see my layout. Note that every piece is numbered and has notes about orientation on it.

4) Load the gun, and apply to your DW being careful to leave a 3" border around the edge to give you something to hold onto. Here you can how I applied the GG, and notice that I left a border along the edge of EACH piece to go up.

5) After you've applied your GG to your drywall, wipe the excess GG off the loader tip on your predefined region of the bucket lip. Next you can do one of two things.
5.a) If you're moving quickly, just drop the loader in the empty bucket (tip down of course). This bucket gives you somewhere to drop the loader that keeps the GG from getting everywhere
5.b) If you're moving slowly, or if you need to take an extended break, cycle water in and out of the loader five or six times in your water bucket, then fill the loader with water one last time and leave it in the water. This was handy for me since I was moving rather slowly putting up all the individual pieces, but it's probably not necessary when putting up full sheets.
6) Rinse, and repeat as necessary.
These are my observations as a first time GG user:
1) I'll say it again,
WD40 is amazing for getting GG of of you. Yep, that's right, WD40 is known to dissolve most substances you are likely to encounter on the planet Earth, and GG is no exception. I don't remember having ever read this anywhere else, but the speedloader came with a can, and as soon as I got some GG on me, I immediately reached for the WD40. I sprayed the GG liberally with WD40, and it wiped right off. However you decide to clean off GG, do it immediately. The stuff is sticky, and whatever you touch will get it on it. If you get it on your drill or ladder, every time you touch those you've got it on you again. I'm fairly certain the stuff violates conservation of mass.
2) I expected it to be a different color green. It's sort of a pastel green, and I was expecting the green on the bucket.
3) It has a pretty strong smell. It reminded me of concentrated latex paint.
4) It's a lot thinner than I expected. I was expecting it to be the consistency of caulk, but it's really more like runny pudding. It will hold it's shape, but it's really easy to squeeze it out of the speedloader.
5) It is sticky, but refer back to 1) above

This is the progress I made.

And this is an ares with carpet above. I'm glad I decided not to do these areas because I had several places where the screws went straight through the DW despite my best efforts.

The next step is dead vents and joist mufflers.