When you do any pressing movement, your triceps are going to get worked pretty hard, so you have three days where your triceps are going to be doing a lot of work. Why not just work each muscle group twice per week with lower volume? For instance...
Mondays:
Chest - 8-10 sets (x 2 compound movements, isolation exercise optional)
Shoulders - 6-8 sets (x 1 compound movement, x 1 isolation exercise)
Triceps - 4 sets (depending on how I feel I do isolation work or bar dips)
** For chest, I may do some bench presses, then superset incline DB presses with some DB pullovers. After my chest workout, I'll flex and then do a lot of stretching. Then I'll do the same after shoulders and again after triceps. For shoulders, I may do upright rows then side laterals, or maybe Arnold presses followed by rear laterals. Switch it up, but know how much you can do and always push yourself. I usually keep my rep range between 6-10, depending on the exercise and which set I'm on. Do power sets, going as low as 4-6, or even lower sometimes. Keep your higher rep sets for the first set of a compound movement to get a little warmed up (10-12 reps 1st set).
Tuesdays:
Legs - 10-12 sets (x2 compound movements, finish with leg curls)
Back - 50 reps pull-ups then 4 sets of compound rowing movement
Biceps - 4 sets (two different biceps exercises, 2 sets each, switch it up)
** For legs, I'd recommend doing at least two heavy compound movements, such as squats and leg presses, squats and hack squats, squats and lunges, or whatever. I like finishing with leg curls, then I stretch a lot. Always stretch a lot after you work a muscle group. Stay warmed up and flexible.
Wednesday - Off
Thursday:
Shoulders - 8 sets (x 1 compound, x1 isolation, you can superset if you want)
Chest - 8 sets (x1 compound, x 1 isolation, superset if you want)
Triceps - 3-4 sets of dips or an isolation exercise
Friday:
Back - 50 pullups followed by 4 sets of heavy rows, then 3-4 sets of deadlifts (power)
Biceps - 2-4 sets (1 or 2 exercises)
Legs - 8 sets (x1 compound, then some leg curls)
I switch it up, but hopefully you can see where I'm going with this. I've been seeing steady improvements in my physique. Technique is everything!
If you want more info on what I do, just PM me.
I used to work each muscle once per week, but this workout routine has been working better for me. I naturally have a hard time putting on muscle mass, by the way.
Peace