I feel your paint!
Spring is lovely, but it's always a moment to see what I've lost. :(

I had the same experience here in zone 4 MN. The oldest JM trees that had exhibited the most hardiness over the years were the ones that took it on the chin. The younger 4-5 year trees came through fine. I think it is in part that the more slender, pliable young trees withstood the enormous snowfalls and pile-up better than those of a larger caliper.

My Crimson Queen bit the dust here in Dayton but the others are ok. I don't know maybe I should look at the shiraswanum but never see them local so it would have to be a mail order. Sorry about all your losses.
Cher

I had a large Crimson Queen that experienced about 10% loss.
Two Shainas- one is fine and the other lost about 50%- that one was the worst hit of all my JM's. My Full Moon one spot over is fine, though.

Several other larger trees (Oridono Niskiki, Nigrum, Jiro Shidare) look bad because the first flush of leaves got frozen, but didn't lose any branches on those.

I had 10+ two year old babies, all of which did fine and are coming on gangbusters. The Sazanami is about to eat my yard it's growing so quickly, lol.

I lost a 10 year old Beni Kawa that was planted in a semi-protected location. From what I have seen online, Beni Kawa is not as hardy in Zone 5 as originally hoped.

I am planning on replacing it with A. palmatum 'Red Baron,' which is not as pretty but apparently hardier.