The way I test them is to remove the movement and tighten everything up with some vaseline on the seals, us eit in a shower/bath and see if it has misted up or not. Done this on my 2 Subs and they were both fine. Not sure about how to make PAMs watertight as there doesn't appear to be any kind of seal on the crown stem. Receiving 45mm PO from Andrew soon and will be doing the same to this watch.