Roger-
You shouldn't have any problem at all doing a Rockwell reading on the blade or test pieces. 15N20 is pretty much 1075 with some nickel in it for flash in the damascus. It's not like using pure nickel (nickel 200) that won't harden during heat-treat. That's why I, and sooooo many other bladesmith/damascus makers use this mix. It is two high carbon steels that weld easily, forge well, and have very similar heat treating characteristics.
Both of these steels would typically be considered shallow hardening. But if you take a steel like this and do a short soak (5-10 minutes) at the lower end of critical, it will fully harden (like glass).
As Michael will receive the steel, it will have been forged down and normalized twice in the forge. After grinding the forging scale off of it, I ran it through my salt bath. First at 1500, 1450, then 1400 three times. It is easily machined in this state. After grinding and one to three more normalizing cycles at 1400...this blade will go into the austenitizing cycle with extremely fine grain, and will come out that way as well.
Please keep in mind I live in a very tiny town where they seem to do things slower than the big cities...so it might take a couple more days than if I lived in Seattle for the mailmen to get Michael the steel.
I'm looking forward to hearing when he gets it and how it goes from there. He should have no problem cutting, drilling, and grinding it.
Nick