I woulds tick with CLen only - don't combine with a different stimulant. Your CNS might freak out, not to mention what will happen to your blood pressure and heart rate.
Save the other stim's for the 2 weeks when you are off CLen.
I assume you are also taking Taurine and Potassium? And drinking WELL over 1 gal of water a day!
You can take CLen anytime. You might find it better pre-WO or it might be too mcuh with no food in your stomach. You have to find YOUR tolerance.
IMHO, Clen is a waste. I think T-Rex is 800 times better.