Thanks for the kind words OS OK.
You could do that, but you'd have to change the width of the magazine guide's opening to match each magazine caliber, or make some shims to buildup the sides of all the mags to the thickness of the largest caliber mag.
My V-groove magazines are laid out to maximize their boolit capacity. To do this, the channel diameter was also setup to be the center-to-center dimension between each groove (see the C-to-C dimension on each magazine side plate drawing). The following CAD images show the 36 caliber magazine setup with V-grooves and rectangular grooves.
As you can see, for the rectangular groove mag to equal the V-groove mag capacity, the strips must be very short and narrow. I'm not sure you could even nail something that thin.
Personally, I don't think cutting inclined dattos is all that hard or any more dangerous than regular table saw work. I cut the grooves at their full depth in 1 pass using my fence as a lateral datum, and tile floats to drive the work down against the table and laterally against the fence. I haven't observed any significant lateral reaction force in the wood as it starts and passes over the exposed datto saw blade. The same is not true when I tried to make the V-grooves with a router. Because router bits have fewer cutting edges, the active cutting edge applies torque into the work which can cause it to move laterally in any direction. For me, that resulted in a V-groove that wandered away from where I intended it to be (see shaded area in the next picture).
I initially did this design work to (1) satisfy my personal needs and (2) potentially commercialize at a hobby level. With commercialization in mind, I constrained each assembly's size to fit in a USPS flat rate box, and really focused on using the most repeatable and simplistic manufacturing methods available to me. I also focused on making essentially 1 design that could accommodate multiple calibers with minimal changes (preferably just the magazine). So for me, using an inclined datto on my table saw to cut the V-grooves made the most sense. It's "easy" to setup, repeatable and fast. A key aspect of using V-grooves is that the boolits are always centered between the 2 magazine side plates. This allowed me to have the same total thickness for all of my magazines, regardless of caliber. This meant I only needed one magazine guide for a complete kit (ie. I didn't need multiple mag guides to match different thickness mags).
Will you share a picture of a sketch of what you are suggesting? I'm not sure I'm following...