I've talked about this a number of times over the years, but maybe not here.
If you are aiming for a "rule of thirds" scenario, it can be hard to accomplish with just one Adjustable Groover. ?Typically the minimum groove width that a set can do is AT or often a little wider than the maximum shoulder you could do when you split the set and use it as a tenon tooling to do both cheeks and shoulders at the same time. ?The two components when nested together don't always completely hide behind each other when stacked for minimum groove (ie no shims) and thus the minimum groove can actually a little wider than each individual component that will be used to form the two cheeks and shoulders. ?The different manufacturers make them slightly differently, so this isn't always the case, but even if it isn't, you'll still be really close/at the maximum shoulder height possible and is just a pain and very limiting with respect to the range of material thicknesses you can use. ?The 175x8mm fixed groover I linked to above will give you a bit over 2" DOC and is inexpensive compare to an Adjustable Groover that can do the same job, but offers zero adjustability and doesn't on its own give you a tenon solution. ?A lot of folks will use two adjustable groovers, one for the groove so they can adjust it to roughly ROTs, but also exactly match whatever tenon tooling they are using, and another thicker one to do the tenon with lots of buffer room for cheek height. ?Or they'll use one Adjustable Groover and have the groove/slot just be larger than what a perfect ROTs would say and is probably what I would do in your situation where you need the DOC (reach) that only an 8mm minimum set would offer you. ? Since you're not mortising, you don't have to worry too much about having any exacting groove width, unless panel fitment is a consideration. ?
