I think the mouthblock looks fine. The only piece that could use a bit more
refining would be the wedge. Maybe there are some historical models that you
could look at and see if there is anything you could borrow.

I have played a lot with the wedge. the V works well but the rest is a bit dull.
I can't really sand it more as it changes out it fits. Most old planes use a lot
longer blades and wedges. but they just get in the way.
I have tried the more traditional forked wedge with a flat sloped middle but
that was a pain to make and never worked better.

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