More than happy to...
I routinely cut sole bends (half butts) into "ranges" as the strips are called. Cut from backbone towards the belly, as you say, and roughly 6" wide. I set the depth gauge on my 5-in-1 cutter to 6", and in a bit from the rounded butt-end, I scribe a straight line across and start cutting ranges. The rounded butt-end piece, called the "aitch piece"--h-aitch, as in British English for the letter "H"--(no idea where this name came from) is pretty good for hard top-pieces. I number the ranges with chalk, 1 through 8 (7 or 8 is all I get from a bend of Bakers)1, 2, 3, or 4 being the best and firmest ones, and they get softer the higher the numbers.
After cutting up several bends, I sort the 1, 2, 3, or 4 ranges into one stack for cutting outer soles from, and the 5 through 8s for heel-lifts. One range will yield a pair of soles of any length. As I always make "piece seats" (a beveled graft at the seat under the heel) by adding a "piece sole" of inferior Baker's scraps to get the full length, the ranges work just fine.
It is perhaps more economical of leather to cut outer soles as needed to exact shapes/sizes, but when one weighs the effort needed to cut one pair as needed of shaped soles to size by hand with a knife, and wrestle with a bend and store it, cutting it up into ranges seems a fine solution unless you are very miserly. The off-cuts from rounding the rectangular ranges to the bottom of a shoe can be used for last-fittings, piece-soles, shanks, heel-lifts, etc., so very little really is lost to waste.
NOTE: for insole shoulders, I slit them down the spine and using a average sized last to trace round with chalk, I pre-cut rough shaped insoles book-matching them, then numbering each pair with chalk; that is pair #1 from opposite positions nearest the edges, and working in towards the backbone. The pairs cut closest to the backbone will be the hardest, firmest. This throws off very little waste, and insures that the insoles mate within a pair in substance and firmness. Bakers insole shoulders fall away quickly in thickness and firmness as you move outward towards the belly-edge, and some end up as split-lift material. But again, for ease of sorting, storing, and handling, I think pre-cutting insoles is the may to go when working with a shoulder too. From a typical Baker's shoulder, I get 9 pairs of insoles. So, the ratio of bends to shoulders is roughly 2:1. We order twice as many sole bends as shoulders IOW.
Okay, now, you say you have side leather. If you plan to use it for insoles, you might be better off cutting and book-matching if you have both right and left sides. If all you have are all rights, or left sides, just try to sort them by substance and firmness the best you can. If you plan to use this side leather for outer soles, go ahead and cut in into ranges, but I'd be leery of how durable side leather would be for outer soles, unless you beat it out before use to harden and compact it.
Sorry you asked now?
