Rear Pannier Supports
Again, thanks for an excellent post!
I am going to use the stock Dirt Bagz rack system for the older subframe ('02~'03 or '04) and mount that to the new ProMoto rear rack. The Dirt Bagz supports mount to the lower subframe bolt and include longer bolts. (You can get a longer cap screw like the stocker at a hardware store.) This Dirt Bagz mounting system holds the panners away from the wheel, pipe and up some. This system has worked great for me in the past. You can also put the MiniBeta Wolfman bag on top of this, back on the seat, and really anchor it well.
It does mean you will have to do your leg stretching routines to swing your booted foot over the rear rack, if you are a shorter guy, like me.
For a RTW trip the 6.6 gallon tank (6.3 as you note in your installation suggestions) would be similar to the LC4 Adventure setup. You would not have to fill it for known distances, but for the unknown it would give you about 200-225 miles (figuring 35 mpg).