I know this isn’t a direct answer to your question, but I wanted to pass this on.
I was so concerned about my dovetails being perfect that I wasn’t happy, no matter how good I made them. Then I happened across a video or a site somewhere about the history of fine woodworking. The big point I took from it is, don’t worry too much about perfection. The old workers were usually building for quantity. They were great at what they did, but didn’t worry about little imperfections (gaps, chips, etc.) in their dovetails. This can be seen in just about all old furniture if you look close enough. It adds a bit of character, and doesn’t hurt the construction. Just move forward and don’t sweat the small stuff.