I also say keep the bi/tri together. As for chest and back, I DID group them together.
Here is the way I worked it:
* 4 day split
* Day 1: Chest/Back, Day 2: Shoulders, Day 3: Lower Body/Core, Day 4: Biceps/Triceps
* I would do 3 pairs of moves per day (6 moves total every trip to the gym)
* I would do the first pair nonstop... press 10 reps, run to the squat rack, dead lift 10 reps, run back to the leg press, press 10, run back to the squat rack, dead lift 10 reps, etc. until 3 of each move are done
* When you are DONE with that first pair of moves... you'll be huffing and puffing exhausted. You'll probably need a minute to stop the burning and catch your breath.
* The point of SS is to a) help the body to grow faster, b) change up the routine and c) THE MAIN REASON is that it makes lifting aerobic.
When you make the lifting aerobic, it forces your glycogen stores to empty FAST... so say you use all the glucose in those muscles up halfway through the first pair of moves... the second half, you're still running, pushing like crazy, and what that does is force the muscles to burn intermuscular fat in those later moves (thus the burn).
As for rest time, the time it takes to calm yourself down and then simply walk to the next machine, find your DBs, put them nearby if you need them, rack up... that's enough time of rest. You'll find your time in the gym will decrease dramatically especially if you workout at home or don't have to wait for equipment.
I'm a little concerned about the cables with timing, but you might be able to handle that. I just imagine myself being in such a hurry to move to the next move, I'd trip over the cable and screw up.
I'm sure you know what you're doing though.
I got out my book. Here is how I laid out the 4 day split for real:
Day 1: Chest and Back
1. DB Incline Bench Press + Standing Bent-Over Rows
2. Seated Row + Lat Pulldowns
3. Inclined DB Flyes + DB Pullover
Day 2: Shoulders
1. Seated Military Press (Smith machine) + Arnold Press
2. Seated DB Side Lateral Raises + Bent-Over Rear DB Laterals
3. Ab work
This wasn't shoulders, but shoulders had a short SS day, so I did my ab work on this day as well as on any other day I felt like it... but I'd do more on this day.
Day 3: Lower Body
1. V-Squats + Seated Calve Raises
2. Leg Press + Romanian Dead Lifts
3. Leg Curl + Leg Extensions
Day 4: Biceps + Triceps
1. Bar Curl + French Curl
2. Standing DB Curl + Rope Tricep Pushdown
3. DB Hammer Curl + DB Kickbacks
Ulter just told me too that another reason to do SS is that the faster pumping of the blood to keep up with it keeps the muscles more well-nourished with nutrients during pump and the muscles really respond to that.
SS is great for a rotation, 6-8 weeks or a few months. Just make sure you don't make it full time year round b/c the body will adapt, but I know you already know that.
I'm so excited to see how it goes for you! It did wonders for me!