Where did you find 200 PSI Poly roll pipe?
Most lateral (zone pipe) is only rated to 80 PSI. If you are really using 200 PSI pipe, I would see why you would have trouble with the fittings.
If done properly, you should only wave the torch or heat gun quickly back and forth on the outside of the pipe and try to avoid pointing at the edges.
To answer your question, weeping leaks are ok on a zone pipe, that is only on for a few hours a week, but NOT ok for the main lines or the valve manifolds.
Maybe the problem is your clamps. What kind of clamps are you using? I assume screw type. There are a lot of cheap screw clamps out there that blow out when you try to tighten them.....