I'm going to add a different dimension to this thread and say that your long distance comfort on any bike depends as much on your physical conditioning as the ergos and wind protection of the bike. Sure, you need a bike that fits you but the most important thing to realize is that riding a motorcycle hundreds of miles is an athletic activity that requires proper conditioning. From that premise, I'll say that a lot of people chose a riding position that puts them in a more relaxed vs athletic body position on the bike. Bar backs and relaxing more back onto your tailbone might feel good sitting on the bike or tootling around town but over a several hundred mile day you'd be better off in a position more like the GT affords (or even a bit more aggressive) with a more forward lean engaging your core muscles assuming your core has some strength and flexibility.
I'm going to guess that there's a lot of us that are in the 50+ age group where that core conditioning and flexibility is hard to maintain but if you did, you'd be a lot more satisfied with your seat, windscreen, and overall ergos of your bike.
Lastly, there's one other factor that I think is equally significant in a several hundred mile ride and that is protecting your hearing. The more noise you're hearing, the greater your mental and even physical fatigue. You'll be tense and just beaten down by the constant higher volume noise than if you used a great in-ear noise attenuation system. I think that contributes more to neck, shoulder, and back pain than a lot of people think.
'12 K1600GT (gone but not forgotten)
'13 S1000RR (sold it to Allstate)
'14 KLR 650 New Edition (for the off-road ADVs)
'16 R1200GS Triple Black (for all of it)
'16 KTM Super Duke 1290 R (for the inner hooligan in me)