There are two ways to go, have a shop plane down your panels to 5/8" after you glue them up or back cut. The former will save you a bunch of sanding.
Or back cut them. If you are using a router for the panel raising, and if that panel raising cutter is a wing cutter and not a vertical one, you can use it to do the back cut. Just lower it down or raise it up so you are left with 1/4" for the dado. That will give you a nicer looking job because it will leave a slight bevel on the inside of the shutter, not a hard edge (which will not show a perfectly even reveal after a while if it ever does).
Actually, thinking about it, even a vertical cutter will accomplish the same thing Just move the fence out.
I had one customer who liked the look so much, she had me install all her kitchen doors backwards, with the raised panels to the inside. Fortunately, she came by the shop before I had hung them all.
Good luck. If you are in the business, think about getting a real shaper (1 1/4" spindle). With a power feed, they are way safer, faster, move versatile and do a better job.
Last edited by clampman; 10-09-2011 at 09:23 PM.