Thanks, very much, Brice! Your tip for using the router bit to position the LR32 rail is excellent, as is that of drilling only the front and rear rows of holes and using the slide and a vix bit to drill any others once is it decided at what height the drawers are to be. For the first side in which I drilled shelf holes, I did join the rails together and held the ends in position with a combination of a Festool clamp at one end and spring clamp or two at the other. But instead of using the stops to position the rail, I drew pencil lines using a 4 ft level (one that I know to be rather straight) or the joined Festool rails as my straight edge. When I think more about my technique, I realize my errors may be due to using 3 positionings of slides along the height dimension, with each being referenced relative to the back edge of the cabinet which edges have the factory cut, which may not be truly straight. And two points define a straight line, 3 points may or may not. My middle and topmost center points for the rearmost row of holes define a very slightly different straight line than my bottom and middle points! I am about to go and try laying out and drilling the holes for the second side.
Last night I drilled the holes for the other side of the large cabinet using much of the technique contributed by Brice. I also too extra care in joining the guide rails to ensure they were straight, and used one of the drawer slides as my template for marking the relative location of the 5 rows of holes. After drill all 5 rows of holes indexed off the bottom of the cabinet, I switched the positions of the "holed" guide rail and the non-holed guide rail. Before drilling any more holes I confirmed the front-to-back alignment of the guide rails by postioning my router on the non-holed guide rail and tweaking the position of the rail until the router bit could be plunged perfectly into a previously drilled hole. (Obviously, all this was done with no power to the router!) I checked the holes against my drawer slide template when I was finished, and the registration was quite good, noticeably better than the first cabinet side. I glued the cabinet box together this evening using eleven 5 mm dominos per joint plus stopped rabbet and dados (which I should have skipped). Using the router bit with the router on the guide rail is much more accurate than using a 0.5mm lead pencil and digital caliper/depth gauge, at least for me.
While working on this, I thought of one more idea that I will probably try the next time I want to use the hole drilling jig, and maybe before for use with the TS 55 or router on the guide rails. I am thinking of making a simple extension device to use with the side stops. One possibility is making for each side stop a simple clamp that can grip the end of the metal indexing rods provided with the side stop, and also grip a length on dowel having an OD sized and shaped similar to that of the metal rods. A pair of wooden clamp jaws with a hex or V-groove should work. Another stop that can be fixed at any chosen distance from the guide rail end of the stop would complete the extended side stops. This setup could be added and removed without disturbing the "zero" setup of the side stops that is necessary to do before using them the first time with the hole drilling jig. If I made a pair of hexagonal rods, I could use the factory stops. I should be able to do that using a jointer followed by a thickness planer.
Those who have sources for metal rods and metal working skills should be able to fashion some extended hexagonal rods from aluminum. I note the factory index rods are large enough in cross-section that they could be drilled and tapped in their ends to enable adding extensions.
Dave R.