As above, Cubester is playing a match for cadets and so I may not be able to make it. For what it's worth Degla red is 12km long, and is easily doable in less than two hours. It's strenuous inasmuch as you have a loooooooong climb up to the start of the fun, but after that its not particularly technical, flows well, and has a bit of woodwork to contend with. The last couple of Km have some great chutes and switchbacks, but berms and in-trail jumps are the order of the day. It's all rollable.
Folk say the blue is great fun but I've never ridden it, and the black has a couple of places to concentrate, and is mostly rollable drops and jumps, with a bit of woodwork that you can't avoid, but won't kill you, and a boardwalk with a drop in the middle that has a chicken run round it.
If I were to make a suggestion, it'd be a mass ride round the red, followed by a cake stop. Keen folk will easily manage a second lap, especially if its the blue, or of course there's always the skills section, berms, drops, steps, boardwalk, tabletops, rock gardens. Easily enough entertainment for a whole afternoon.
I'll do my best to be there, but don't count on me. I'll know by late tomorrow evening.