I have still few pipes which accepts removable metal stingers ,mostly French make but also one GBD the problem is that mortise in these pipes is hollowed open to accept those clumsy stringers ,shank walls are quite thin in these pipes, and when smoked without stringers ,the draw is wide open akin to Corn cobs whereas when smoked with stringers inserted they will unavoidable start collecting moisture, to remedy this I use to put some meerchaum chips in the bottom of the bowl or alternatively I'd use 4mm Denicotea paperfilter which aren't much of help but will restrict the draw in some degree