Try other top bags, you want to minimise what you put in the under saddle bag to stuff you wont have to constantly get to- the less you access the better as they are generally a pain and are ideally loosened right off/taken off completely and refitted if you are taking stuff out/putting it back in.
I know - it's why I had the Revelate to try.
I don't really know any other bags and it's getting late in the day to ask for custom.
Does anyone make a -skinny- full length ones?
Top tube, they are much smaller though so I wouldn't rule out a frame bag until you've tried every variant. The apidura annoyed me initially but with a bit of pummelling/centralisation was fine.
Try other top bags, you want to minimise what you put in the under saddle bag to stuff you wont have to constantly get to- the less you access the better as they are generally a pain and are ideally loosened right off/taken off completely and refitted if you are taking stuff out/putting it back in.