The big un QR system is a solid axle. I've yet to come across anything different. The problem would be the end spacers, which are pretty much the same as other solid axle hope spacers only larger.
There should be pics in the Hope timeline thread. I'll take a look
Heres a pic of what one looks like
There is another solid big un axle, pretty identical to the bulb/ etc axles. There will be pics of it somewhere on here. The difference is it is fatter and you can pretty much tell by looking at it that its for the big un hub
View attachment 628917
This info has been discussed multiple times over the years.
https://www.retrobike.co.uk/threads/hope-disc-timeline.94741/