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If you remove the scratches before HT, then the scratches will not be much of a problem. I usually finish a blade at 240 before HT, because the same grit makes a lot deeper scratches pre-Ht than...

AO is cheap
Ceramic is robust

Zirconia is neither :D

Don't buy aluminium, zirkonium or silicon belts for roughing out blades. They wear very fast.
Buy ceramic belts. They're more expensive, but last much longer and stay sharp longer.

As an aside:...