My balance is a little wonky sometimes. It's almost always due to chronic allergies and congestion in the sinuses and eustachian tubes.

I'm usually skeptical about herbal, homeopathic and "natural" remedies (there's nothing unnatural about Sudafed or pseudoephedrine -- it's very similar to ephedrine which was synthesized from ephedra, a naturally occurring decongestant and bronchodilator). But I tried bromelain this year, an enzyme from pineapple. It's supposedly good for inflammation, especially sinus inflammation. It sure seems to help me. So does niacin (Vitamin B3), although at first there's some flushing and stinging sensation. But that disappears after a few days. It helps clear my sinuses too.

When I resumed cycling in 2015 I hadn't been on a bicycle in more than 30 years. Took awhile to get the hang of it again, including handle a water bottle. It helped to start with a bottle with a grab loop -- some Polar bottles include a grab loop. Not sure about Camelbak, mine doesn't have that. But I could swap the same plastic tether between bottles.

By now I don't think about it much. Helps to practice while on the indoor trainer. Muscle memory so I don't need to look. But when I switch bikes and the bottle cage is set a little differently, I need to look a few times until I remember where the cage is.

And it's possible you may never get comfortable with the downtube bottle cage. A couple of friends don't like them. One in particular has chronic balance issues that may have been related to chemical exposure in a former job. Those two fellows, and other folks I know, prefer Camelbak backpacks for water.

I kinda wish handlebar bottle cages made a comeback. For folks who are accustomed to handlebar bags it wouldn't be any worse. Many road racers used handlebar bottle cages until the 1960s.

There are also collapsible bottles that fit into pockets. I have a collapsible Mylar squeeze bottle that I carry in my jersey pocket in summer. I freeze it first and with electrolytes it'll stay cold and keep my back cool for a couple of hours before I need it. By then I've gone through my two regular bottles.