Re fanny packs, I can't imagine riding with them because I used a camera fanny pack and lens pouches on the belt for ages working. They work great compared to a camera bag but do get tiresome after many hours. I regularly shifted positron of it during long assignments, but sure wouldn't want to ride with even a lightish one.
but only way to know is to try.
RE: shifting positrons
"The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e, a spin of 1/2, and has the same mass as an electron. When a positron collides with an electron, annihilation occurs."
NEVER shift positrons in a fanny pack when riding a crabon bike! this is when assplosion occurs!
https://3.bp.blogspot.com/_V54WWNeyy...s400/museu.jpg