There are many applications of the LR-32 System. A whole lot of books are available on this topic.
Where nearly everyone agrees is that holes for adjustable shelf pins are drilled on 32mm centers (or centres) mostly because way back when, using available gears, that was as close as drill bits could be located on line boring machines. So, by logical extension, cabinet heights were in multiples of 32mm. Originally and for years after, LR-32 was an accepted standard to make manufacturing cabinets more efficient.
If all the hobby or custom cabinet maker is using are adjustable shelf holes the set-back from the open front edge and in from the back can be any thing you want. There is much to be said for having the front holes fairly close to the edge, so if the first object placed on the shelf is heavy, the shelf will not tip forward. By the same token the rear holes should be close enough to the back that when a load is at the rear of the shelf (a typical situation) the front of the shelf will not tilt upward. In cases such as book shelves with shelves not more than 12" (300mm) the popular 37mm set-back works well.
Things get tricky with deeper cabinets, such as in kitchens. To better support the middle of the shelf the tendency is to increase the set-back, to reduce the span between shelf pins.
It has been noted that IKEA uses a 27mm front offset. That works with the hinges and drawer slides used by IKEA.
The important thing is to read and understand the instructions for the brand of hardware you are using. I have been designing and building LR-32 cabinets for 60 years. Probably the majority have used a 37mm front setback. Still, I have to be careful, when working with unfamiliar hardware, to use the setback specified by the manufacturer.
Placement of the rear holes is a function also of the design of the slides. Almost always the spacing is a multiple of 32mm, but not always. Clearly it is convenient to have all the rear holes the same set-in from the back. Just do your best to avoid spacing the holes so wide the shelves sag or having the rear hole set-in excessively so shelves tip.
The Festool LR-32 guide rails are marvelous. Festool provides linear stops to establish standard vertical position.
Personally I use the top of base cabinets and the bottom of uppers as the vertical reference since those ends are not scribed. Often the first holes are 80mm from the reference. I usually skip that hole because my clients find it pointless to have a shelf so close to the top or bottom.
