rivers, very good points to bring up about smaller frames. My wife rides an XS frame and while she has no interest really in bikepacking and less volume carrying, we can very much relate to how you run into space constraints with smaller frames.
Ive only recently started playing with bikepacking setups and I'd have to say that while I've noticed the shift back to racks and small rear panniers over the last few years, it does make sense to me and I don't see a real downside to it unless one is really going to be super critical about overall weight and pushing daily distances or average speeds if that is your thing.
Seems to me that for most people, going some sort of rear pannier route makes things easier for more average storage volume (less extreme minimalism) and making things easier like front end aspects--- I have used fork cages and smaller drybags, but did notice that I didnt like how taller drybags touch the frame in very slow, see-sawing handlebar maneuvers. On my bike, the fork cage mounts are facing towards the back of the bike, so make the bags more likely to touch the frame unless I made the drybags short by rolling down them more so they clear better.
What width bars are you using? I switched my dropbars from 42 to some 46cms that I bought used a few years ago, and using a Revelate harness, I can fairly easily put in a 10L drybag and my tent, but as I am using Gevenalle shifters, not STI , on this bike, it is easier as I dont have to make room for the shifters moving inwards like regular sti .
your custom frame bag seems to be the best option for water access. Thanks for the referral, I'm sure this could be helpful to others with small frame triangles.
On the water bottle topic, with drop bars I still really like using the tops as a reflex hand position when going over rough stuff, and when climbing steep hills, so having water bottle bags hanging near that area would be annoying to me, not to mention getting out of the saddle and having knees going there---caveat, I havent ridden my bike with bottle bags there, so don't know if they would be okay, I could be wrong.
all in all its kinda fun playing with and figuring out different ways to pack stuff isn't it?
My handlebars are 40cm c-c, with a 16° flare. They're about as wide as I'm comfortable with. I don't have a problem with shifting now that use a handlebar extension to take the bar bag up and away from the headtube and front wheel.
A hydration bladder in the framebag is ace. I used it this weekend on a gravel sportive as it was absolutely roasting. We're in the middle of our first heatwave of the year. Apparently we're in for a long, hot summer so may just keep the hydration bladder on the bike.
my set-up for my next trip will once again be completely different as im taking my 18 month old son in his trailer. The terrain will be a bit easier however