Carl Z

Are you talking of spalted wood?

isn't spalted a natural process?  This is the embedding of voids with a synthetic filling. 

Here is a page that shows what can be done, but it is for the material, not blanks.

https://www.alumilit...ies#prettyPhoto

If you like them, they will work fine.  People put single foot guides on bamboo and the world doesn't come to an end.

If it's your first build, read the old posts about working with REC guides.  As I recall, the flexibility and hardness makes prep work a bit harder.  I haven't used them myself.  

Neat looking blank, but I can't place it.  It doesn't look like Orvis or Fisher, which were what I was thinking of.

A picture of the ferrule and label might help.  Strange as it may seem, the handwriting on a label can be a big help.

Fisher, Orvis or Fenwick are my thoughts. 

Sanded or unsanded blank? 

If it doesn't come back, ping me. I have a version in python but could convert it to something more universal if need be.

I don't recommend guide sizes, just placement.