I just started trying this (only 1 week in). I'm going to play it by ear: While it seems to be completely ok for me to do STS 6 days per week now in Meso 1, I will definitely put more rests days in if I need them when I go heavier in Mesos 2 and 3.
I am at the tail end of a bad cold, so I haven't been doing cardio- just STS and yoga. I plan to start adding in a couple of short (20-30 min) cardio sessions per week though. So far, my workouts look like this:
Day 1: Disc 1 (Chest, Shoulders, Bis), abs, yoga
Day 2: Disc 3 (Legs), abs, yoga
Day 3: Disc 2 (Back, Tris), yoga
Day 4: Yoga
Day 5: Disc 1 (Chest, Shoulders, Bis), abs, yoga
Day 6: Disc 3 (Legs), abs
Day 7: Disc 2 (Back, Tris), yoga
Day 8: Yoga
I'm on day 7 and down 1 pound- woo hoo! I am blogging about my progress to keep accountable.