Hi digdoo
It can be tricky to set up for the Rail and Stile even when you have the setup blocks, here's a trick I use all the time.
Most R & S bit sets are matched sets, that's to say the cutters are in the same spot on the router bit shank, from the bottom.
Put a rubber grommet in the router collet ,at the base of the collet,this will hold the bits at the same height,now if you use a sled ,that is 1/4" thick the norm just slip a brass setup bar under the cutter, to raise it by 1/4" the norm when you used the router sled.
Your stock can be 1/2" to 3/4" and it will come out right on the button every time.
The grommet must be in tight, in the base of the collet so it can't move or drop down when you put the bit in the chuck.
You can also use a rubber faucet washer,that you can get from a hardware store in a repair the kits for about 3.oo dollars for 20 or so.
Not all router chucks are the same size,ID so you will need to play with it just a bit to get the right size,it should be a tap fit,that's to say tap it in the collet so it's flush on the bottom of the collet.
Bj