Test prop can only be detected for up to 2 weeks i am pretty sure. So you could use that until about 3-4 weeks out i would think but i have never been in a comp before so mabye one of the vets who is more familiar with comps can help you out. Also winny is only detectable for up to 3 weeks after you take your last dose of it.
Stick with suspension and anavar or prop and anavar if the suspension makes you feel uncomfortable. Stop the anavar 3 weeks prior to the competition and the prop as Sir mentioned above.
seriously, if youre gonna juice for a show, dont steal from the natural guys. dont be so fucking lame. juice up to the show and do a non-tested show. how could you even feel remotely good about cheating on such an amazingly high level?