Wondering if you'll be fine with that ratio - you don't need to pack as much food/water processing while bike touring. I'm <25L fully loaded on the bike, and >35L backpacking. Just carry a 3oz Sea to Summit Ultra-Sil backpack for excess groceries or just-in-case.

I tour from a single quick-release 30L (not full) front pannier, tent and poles incl, on a folder. Around where I like to tour, I find ultra-compact/lightweight touring (nearly 2-item airline carry-on equiv) to be truly liberating for: multimodal transport, stealth-camping, and ultimate security (eg. wheel/carry my rig inside grocers/restaurants/museums/B&Bs - clicky).

My tent fly, and maybe tyvek footprint, are the only things that will get damp in the rain and they pack into the fly's waterproof pocket and so everything in my pannier stays dry. Dealing with a single, quick-release, back-packable pannier just makes life a little easier.