Hi Andrew Jackman!
First of all apologies about my assumptions. In my hasty reading of your question I got the impression you were talking about yourself and not the intended audience for your tutorial material proposal.
Like yourself, I too would use a practical, tutorial style guide if it were available. So I would like to give my vote for your idea. Unfortunately, I'm a one-man-show and thus not in a position to make a pledge towards a tutorial effort.
Perhaps the good folks who are involved with seL4 could suggest how your proposal could come about. Reading these digests, tit would appear that there are quite a few people who are trying to come to grips with seL4.
Yes, I was referring to the material that you linked.
Cheers,
Tyga