It depends on the amount of each. I assume you're talking around 100mgs Tren Ace, 100mgs prop, and 50-100mgs Stan... if it's somewhere around this mark (cocktails usually are), then do a minimum of every 3 days. Every other day would be optimal though. Prop's half-life is not very long so you need to do it more than every 4 days. .
As a cycle, this would be pretty decent for a pre-contest run. Personally I would throw in Masteron instead of the winnie (IMO). You're probably not going to gain much size off of this. This in conjunction with the proper diet/cardio/workout plan will add some VERY lean, dense, and vascular gains.

I'm hoping I answered what you were looking for....wan't really sure of the question.