You did not mention the depth of cut you are after. I recently slapped myself for selling my 200 mm CMT dado after getting my Felder dado set, why because I found out it does not cut very deep. I guess it was designed for use on the saw where more depth on tooling is not usable but they could have designed it with use on shaper in mind. So if you would like to get an adjustable groover that will also work on shaper (30 mm spindle) and would like deeper grooves on shaper then get a dado instead of Felder dado. The dado sets can be had with flat bottom, so no bat ears. Keep in mind that while saw will accommodate larger dia tooling, shaper is limited to table opening (if you want to lower it below table), so 8” is what I have seen available even though the opening is larger.

After going thru this exercise, I just bought the following from ridge carbide in 1 1/4” bore but it is available in 30 mm as well. I am not sure if 30 mm comes with the 2 pin holes or that is extra. This is 8” but 10” dados are available which will go deeper than the Felder 228 mm dado but again 10” is too big for standard shaper hood.