The thing is Jason, those dovetails (as is) will hold forever and only have some cosmetic irregularities showing. We all want to do better in whatever we attempt, so I understand where you are coming from, but those dovetails are nothing to look down on. You can use a coping saw with the thinner kerf Japanese saw by inserting the coping saw (or initiating) cut with a "sawing" motion in the air just above the vertical saw cut kerf so that the saw is "sawing" as it is lowered through the kerf to the point where you want to make the turn to start making the baseline cut. The coping saw will just scuff the thinner sides of the vertical saw cut as you lower it and does not harm the saw cut at all. A thinner bladed fret saw or the Grammercy saw eliminates that need, but I tend to start "sawing" before I reach the bottom of the vertical kerf anyway as a habit even though I now use a fret saw.