I also got the longer leg Scott over trousers and had stirrups fitted. As you say it’s that dilemma of ‘should I stop, but it’s not raining that much yet’ vs ‘I should have stopped earlier as I’m now wet and struggling to get them on’ vs ‘For f*cks sake I’ve only done 5 miles and it’s stopped raining!’
I think the Kriega US40 is designed with camping gear in mind. https://www.infinitymotorcycles.com/product/kriega-us-40-rackpack-black-one-size you can then add the smaller US bags on top.
Aluminium 'GS style' panniers are good for volume, assuming you have the standard plastic ones on now, can also strap stuff on top if needed, keeps weight low down too.
Okay, I'll answer the actual question (someone has to) Yes to Kriega. I use a 20L bag mounted on top of each of the panniers and. as I use Scott waterproofs and Knox layering, I store all the various layers I am not using in these. I further secure them with Oxford Tie Wrap combination locks, to stop the casual thief and also to secure our helmets. The inside strap just goes around the pannier mounts. To mount the outside strap, I use a bungee from the pannier base mount to the pannier hinge and thread the strap through this, forming a kind of 'X'. Very pleased with this system.
Thanks for the responses ... after looking around at Shad, Mosko and every other luggage brand offering it's seems like a resounding YES to Kriega but NO to additional capacity. No rush though so a couple of short camping trips and another long tour should refine my "happy place".