Re: Twice a week...
I would alternate upper and lower body so you're not overtraining and allow enough time for recovery between workouts. Since you're hitting each muscle twice a week, you only need one or two exercises per muscle group each time. If you're doing presses and rows, you don't necessarily need to do isolation exercises for biceps and triceps which can save some time. Squats will take care of most of your leg needs also. I'd split it up something like this:
Mon: chest/back/(lateral)delts/arms - if you think you need it
Thu: same as Mon
Fri: same as Tue
Keep in mind, if you start to get fatigued, burned out, overly sore or losing strength or mass, you're overtraining and need to change the workout.
Just my $0.02
Keep your body lean, your blood clean and your mind sharp. -Rollins