NK3D Common Base for Shed and Kayak Accessory Mounts

I kept designing one-off mounts and solving the same fixing problem every time, so this is the one base they can all sit on. Screw it down once, then build whatever receiver you need on top of it. It is 58 by 35 mm and 7.4 mm tall, a tapered dovetail body with two countersunk holes on 40 mm centres. On a shed wall that is two countersunk wood screws. On the kayak I am planning M5 bolts into well nuts with a proper support pad underneath, but choose your own hardware for your own hull and backing, because the 5.5 mm holes in the base are not hull drilling sizes. This is the base on its own. There is no receiver, no latch and no accessory yet, so it is somewhere to start your own design rather than a finished mount. If you are building one, it has to clear the full 7.4 mm shoulder and both end rims, not just the 7 mm deck. Nothing has been printed and pulled on yet, so treat the first one as a prototype and do not hang anything on it you would hate to drop. PETG, flat side down, 100 percent scale. If you build a receiver for it, tell me in the comments what you made and what you would change about the base. That is what decides what the next version looks like.