I have 2 DeWalt DW618 routers with the D handle bases that I use with my D4R, but I use 1/2" shank router bits with them. It doesn't take long to realize that you really need 2 routers, 1 for the straight bit and 1 for the dovetail bit, because once you get the bit heights exactly right, it will not be efficient to have to remove that bit to switch bits and then perfectly set the second bit, only to need to change back to the first bit again.
Having two routers (don't have to be identical) makes a huge difference in your ability to produce good joints quickly, especially when doing many drawers, etc. at a time. I also found that you don't need high horsepower routers for cutting dovetails. 1 hp is enough for dovetail cutting, but you need the capability for the larger 1/2" shank bits because there is too much flex in 1/4" shank bits. The smallest routers that seem to be available that can accept 1/2" collets are the 2 - 2 1/2 hp size. A router that is light in weight and has a low center of gravity is important if you will be in production mode cutting dovetails all or most of a day, because your arms will give out if they need to lift the routers on and off of the D4R all day. I built a platform the same height as the D4R with a hole in the center and locate it just behind and off to the right of the D4R, so I can place the in-use router there while changing the work piece. This reduces the amount of lifting that I have to do. I found that the DW618 routers were the lightest 2 1/4 hp routers that I could find, at the time that I compared every popular brand that was available, but this was 10 or more years ago. I bought the DW618B3 three base kit and found that I liked it so much that I bought a second DW618B3 kit to keep in my truck. They became my GOTO routers for most of my work. When I tried making dovetails using the D handle base I liked it so much that each time since then that I got the second DW618B3 kit out of the truck so I could use both routers with their D handle bases to cut my dovetail joints.
A word of caution though - If you do go with two identical routers, put a piece of tape on the top of each router motor and draw a picture of the bit that is in that router, so you don't pick up the wrong one DAMHIKT.
Another suggestion - Centering the router bushing is not nearly as important if you draw an arrow on the top of each router base and keep this arrow pointed toward the D4R each time that you cut the dovetail joint. A slight error in the bit to bushing centering will not affect the joint if it is always in the same direction. Keeping the router arrow pointing toward the jig every time that you make a cut will solve this problem. The entire joint might be shifted left or right by a few thousandths of an inch, but the joint will have no errors within it due to this bushing to bit centering error.
I also learned to make 2 passes when making each cut. The second pass was to more carefully follow the guides of the jig to make certain that I hadn't missed an area or not followed the guide close enough on the first pass. It's nearly impossible to go back to re-cut a missed spot once the work piece has been un-clamped from the jig, so making the second pass pretty much guarantees that the joint will fit together.
When first using the D4R, my biggest mistake when first using the D4R was failing to drop the guide back down against the work after replacing the work piece. Making the cut without the guide lowered destroys the work piece. I made myself a check list and followed this to keep me from forgetting again. It worked for me, most of the time. I have now learned to always plan on having spare work pieces for each job, because this, or other mistakes can and will happen.
Central North Carolina