Thread: Cracked Edge

My restoration project has come to halt due to a crack , just over 1mm tall , 4mm from the tip and I need a bit of advise please.
I figure that to start off I should breadknife the edge. It would ensure even metal removal along the entire edge. Even though the crack is at a part of the tip that starts turning upwards.
Also honing at any other angle apart from 90 degrees may cause the crack to lengthen .
What I'm not sure about is what hone to start on.
I was going to use the Shapton 500k but now I'm thinking should I use a Atoma 1200 , I have a new ish one and a worn one. I also have a DMT 325. The problem with that plate is that there is a cluster of diamonds that even after much effort haven't been able to sort out..
I've never took a blade to a diamond plate before so im a little bit dubious .
Thanks