@Bowers, Disregard my remark that 5.25" AL40 bands would be hard to find. I looked again at the 5.5" bands, and they list as working for 5.25" AL40's. Which makes sense as the center plates would just be pulled 3/4" closer (circumference = 3.14 * diameter), presuming they built them for that to work. If yours really are 4"+ that is a different story.
AL40 twins look appealing for being less negative, but my thinnest NorCal suit should still give me reasonable ditchable weight with LP50s. Even though LP50 doubles look 7 lb. negative empty ((2 x 1.24) tanks - 4.8 manifold - 5 bands) without regs. People do add crush resistant foam or air tubes to make cameras less negative, I could add a few pounds of lift to the doubles and matching lead to me if needed. It would be awkward to help teach with very little ditchable weight on my recreational doubles, when we emphasize having ditchable for surface safety.
thank you for looking into that. it will save me some work trying to make my own.
i will eventually have a variety of options but for now i already own a couple 40s so i figured id give it a try. with a 3 mm full with hood and gloves i am heavy using a steel 72 and my aluminum backplate, so even a double 40 should be very little required ditchable weight if any (im a dense guy lol)