Steve,
A bit more information about how I ended up with the FMT jig and some more tips.
You will need a router that can take both 1/4 and 1/2" bits but a huge and heavy router isn't a good choice. I usually use one of my DeWalt DW618 routers with my FMT jig. The router base of this router has matching holes for mounting it directly on the top plate of the FMT
When I first bought the jig I tried using a heavier router and I wore out my arm muscles lifting it on and off of the FMT. The 2 hp size routers work fine on an FMT jig with plenty of power for the job, yet are light enough to lift on and off of the jig frequently.
I built a wood platform to hold the router that's the same height as the jig and place it behind and off to one side of the FMT so I can almost slide the router from it to the FMT and back. For me, this has proven to be very handy. Leigh says that the router does not need to be removed between cuts, and is only necessary when needed for alignment of the first piece to be cut, but I've found that I want to see better when removing and replacing each piece , so I frequently remove and replace the router when I'm using the FMT.
I bought my FMT Pro jig when I was faced with a job that needed over 1,600 M&T joints and it paid for itself several times over on that one job. Before going to the FMT I had researched every way that I could find for cutting the joints faster and more accurately. No other M&T jig on the market had this fine adjustment capability, and no other jig that I tried made joints with the repeatable accuracy of the FMT. Back before purchasing the FMT I had first started making M&T joints the old way using mortising chisels, and my drill press using square mortising bits, then I bought a square chisel mortising machine when the drill press wasn't adequate, then built a router mortising jig from wood, and made floating tenon stock using my table saw and planer, and I then bought a Mortise Pal floating tenon jig. I was about to go with the Mortise Pal and floating tenons for this large job when I bought the Trend M&T jig. It worked and could do both the mortise and the tenon, but it wasn't nearly as repeatable nor did it have a fine adjustment capability So my M&T joints have evolved over many years learning curve before I finally bought the FMT.
Two years after buying the FMT, I sold the Trend jig for about 1/2 of what I paid for it. I had only used it for 2 days when I decided that it wasn't capable of doing what I needed as accurately and repeatably as I was expecting from it. The Mortise Pal has now been sold too, and I now do all of my mortise and tenon work, and even floating tenon work using my FMT jig.
If you should ever decide to use floating tenons (they are sometimes a better choice for certain uses), cut the mortises in both pieces instead of just one using the FMT. Then cut long stock for the tenons the width and rough thickness that you will need using your table saw, and then plane them to the exact thickness needed with a planer. The edges of this tenon stock doesn't need to be rounded. Just make them the width of the flat sides of the mortise that they are being made for. Then cut them to length as they are needed, making them about 1/8" shorter than the total depth of the two mortises. The 1/2 round mortise hole left at each end of the mortise that the square ended tenon doesn't fill becomes a good place for the excess glue to go. The flat surface side areas of the tenon and mortise are where the joint strength is anyway, so these 1/2 round mortise end areas aren't needed for strength. You can round the edges of the tenon stock if you want to, but why do it if it isn't necessary. I've never had one fail when glued with Titebond II.
Charley