Good choice roger, the best. but I would be tempted to use resiblock 22 as it's a one coat application so easier and quicker as opposed to superior which is a 2 coat, and 22 is also commercial grade so stronger, superior matt is domestic and a 2 coat system.
I think resiblock give a 10 year garentee agains loss of jointing sand to their large scale commercial clients with the 22.
Used them both and prefer 22 everytime when it comes to matt.
No offence Roger, not under mining you, i have respect for you as I know you have lots of experience and been doing the job longer than most on here, just offering my opinion too