Here's what I would do: Plane em down to 1", route the dovetails, build the box, then build up the edge with a tapered wedge maybe 1-2" wide, going from 0 thick to 1/4", and glue them so the 1/4" is on the inside of the box making it appear to be 5/4" thick.
Done right I think it would also add additional style to the piece, rather than just being a box.
I *love* my D4. For through dovetails it takes 5 minutes to set the thing up. Just make sure you route them a *bit* deeper than the thickness of the board so you can sand them smooth after they're glued up. DON'T try to make them perfectly flush.
For half blind, it takes a bit more setup since you only get one shot to make them fit (with through DTs, you can creep up on the fit). What I recommend is that you make a test pair of boards so the next time you do a half blind, it takes just a minute to adjust everything.
I can understand why someone would want to cut them by hand, but I don't have the patience or time to learn to cut them equivalent to the quality of the D4.