The whole point of SST is that it produces a lot of the same adaptations as training at threshold, but takes less recovery so you can do more of it. So SST + Threshold doesn't make a whole lot of sense except maybe for masochists training for TT's.
VO2Max and Anaerobic work hits different systems and produces different adaptations. So SST + VO2 makes more sense, just make sure you have some easy and/or recovery days in there. Doing 4-5 days of SST plus 1-2 of VO2 during a week sounds like a good way to burn out.
Great points. I take Wednesday, Friday & Sunday off.