I'm also an FMT user, but if you make a guide for your router to make mortises using standard up spiral router bit diameters and then use your table saw and planer to make tenon stock for those resulting mortises, floating tenon joints aren't that hard to make and are very strong if made carefully. I tend to use my FMT Pro for both standard M & T as well as for floating tenon joints now, mostly because it's adjustable, but it's easy to make a dedicated mortise jig for your router if all joints will be the same size and the same distance from the face side of the work.
Using your mortise jig and the same router bit to cut mortises in both parts using a guide to get them exactly the same distance from the face sides of the work is quite easy. Then cutting your tenon stock to fit the between the flat sides of the mortise so they don't rattle when inserted, but don't require a hammer or force to insert them either, will produce excellent floating tenon joints. Although the mortise will have rounded ends and the tenons not doesn't matter. The strength of the joint comes in the fit and the glue between the flat surfaces and not the rounded ends of the mortise or tenon. Leave the 1/2 round ends of the mortises as a place for the excess glue to go and just go with the square ends on the tenon stock to fit the flat sides of the mortise. Their thickness is important, but they are easily made the right thickness in long strips using your planer. Cut them to width using your table saw as you need them. Cut them to length by 2X your mortise depth minus about 1/8" to assure that the tenons won't bottom out before the two work pieces meet each other. I just chop them to length as I need them using my miter saw and a stop.
Charley