Howard and Val -
i was thinking along the same lines as Mark (but Mark thought of it “better” … i.e. more specifically, how to do it).
As someone pointed out, Garhauer is remarkable in that they seem to bend over backwards to help the individual sailor - custom orders of small items, changes to existing items, etc. and all of it reasonably priced. They do have this wonderful reputation. And, their products are excellent.
Supposing you called them up and, crazy as it may sound, ship them the old blocks (and in your case, Val, the new blocks you ordered that don’t quite fit). Just maybe, they would/could rebuild the block using the old base, etc. as they have the machines and know-how to put blocks together. While, technically, they may not be able to warranty the block in the same fashion as their stock items (or an item built of 100% Garhauer parts), I know of no one who has had to return Garhauer items to their plant for warranty claims - they seem to last a long, long time.
Or they could … who knows ?? They may have an answer and it may not cost the earth. It might be worth a try.