I wish you luck, finding a light bike that will do what you want it to do.

I've tried many different light set ups, none seem to work the way I wanted it to.
That includes a full blown custom. Nice bike but it still came in as a 28 lb monster.

I ended up with a vintage sport touring type bike, with a good set of wheels!

I hope it all works out for you.

The ortlieb or caradice bags are both easy to use and work well.

Good luck