hi MotoGuitar, first of all you gotta believe what ALL the books/videos/weblists say:
A bloke can travel so incredibly light - other animals in the travel world (cage drivers) would undoubtedly think t's rude !!! hahaha
Assemble everything you think of needing,
spread it out on the floor, remove half the amount of all items,
put the remainder on your bed, look at it carefully - and remove half of everything again - and
put what remains on TWO kitchen chairs. NOW comes the hard part: Reduce the amount of what you have left
until what's left fits onto ONE kitchen chair. Presto! you're done
My typical stuff for an average 10 day trip fits into ONE 2/3 size pannier liner (they are a very good idea if you're using panniers) which is roughly 450mm x 180mm x 180mm. That includes a book, a sketch pad and pencils/pens/ etc. On my C, light shoes, rain gear and camera go into the top box (that's for 2 people, my younger daughter rides with me). My daughter's liner is 1/3 larger and she manages to fill it right up (yep, girls travel heavier

)
I'm not too proud (or unskilled) to wash clothes every 2 days in the motel shower

, it drastically reduces the need to take along heaps of stuff - in summer anyway.
For the R9T I've chosen 2 Vintage style canvas barrel bags (lots of leather straps, buckles, good attachment points) which I'm going to modify into a pair of saddlebags. I'm going to remove the original seat and make a custom comfort seat for rider & pillion - and hopefully it'll all come together to complement the bike nicely. I found all saddlebags on offer are too black, too high tech looking (streamlined, etc). Hard panniers would bring the R9T closer to a R1200R look - not what I envisage for this roadster ....
Re-reading what I just wrote, if I was riding solo, all my stuff wold fit into one of those canvas barrel bags and strap on the rear seat. But then I would also rough it more (than when travelling with wife & kid) and take along my swag to sleep out - which would bring the saddle bags back into play.
Have fun deciding