Your Weston sounds pretty good to me
I don't have any Westons but I've got a couple of .50GT's
Most I've seen is 14,700 with an APC 10X7 and stock muffler, on 10%, which hauls my Tower Kaos along nicely.
Mike...what is the I.D. of the Weston's venturi? Stock Webra .50 (and .61 Speed ) is 8mm