I've made these two rabbets planes by copying a larger XVII century exemplar. The main characteristic is that it has only one open side. As a blade I used a file, properly shaped and sharpened. The body is mahogany, the sole wenge. The metal bar on the side avoids flexion body when the wedge is forced into place and adds weight to the plane. You could avoid increasing the plane body thickness or decreasing the width of the blade, but in both cases these are uncomfortable compromises.
The hole for chips ejection can be easily achieved with a Forstner bit. The body design is very close to the original and I must say that the fingers have a perfect support.
Having only one side useful for working you have to build two twin planes, each working in one direction. One use for wich I found convenient is to finish the rabbets. In this one, made with the circular saw, I screwed the setting of the blade and the result was a visible residual step. A simple job for one of the little twins!