I love kangaroo and cook it almost every week as I can get it at my local supermarket. I agree there is very little information on the web about cooking kangaroo sous vide. I emailed Macro Meats and suggested they come up with something in their test kitchen but so far nothing.
My approach is to follow Doug Baldwin’s excellent advice in A Practical Guide to Sous Vide. (If you don’t know him I recommend googling him.) So pick the level of doneness you want and then cook for the time specified in his table for meats based on their thickness. I like to cook mine at 57 C for about 75 minutes as it’s usually about 25mm thick at its thickest. Then I sear for a minute or so each side using one of the usual methods. Before bagging it I usually salt it but I keep the preparation simple.
I haven’t tried cooking it at a lower temperature than 50 degrees and I found that a bit too rare for my liking. Also i feel nervous about cooking it at low temperatures, given that this is a wild meat, although it does get visually inspected for worms I believe. I’m no expert on this but I believe that a good surface searing on all sides is important, and it shouldn’t be served to immune compromised/pregnant people.