At your stage of gear, i can`t imagine how its possible to not clip envenoms, especially during execute. Much better to lose a second or 2 of clipped envenom, rather than sitting on full energy waiting for envenom to drop <2 seconds.
Just think about the reasoning behind why you avoid clipping. It is just so that you maintain a higher envenom uptime. As long as you aren't getting stuck without energy or CPs when the buff is about to fall off, just go ahead and envenom early.