Berwyn bindings have been used for years by many notable expeditions to both poles and throughout polar lands. They are principally used with mukluks, which, by their very nature, are not intended for use when great ski control is required.
Ideally, users should have good experience of skiing before using these bindings. They should be used with care, particularly if travelling over uneven surfaces like pack-ice. Spare heel pieces should be taken in case of breakage – maybe a few within a group. (The heels are left- and right-handed, on account of the way the buckles face, not because of the moulding shape.) The toe pieces are moulded for left and right feet.
Berwyn bindings are adjustable for boots sizes, but the widths of different makes of boot, for the same size of boot, will vary. Baffin boots are very wide, certainly for their lower temperature rated designs, and the only way that their sizes above about size 9US, (8UK), can be fitted now is to ignore the binding instructions and to drill out pairs of holes towards the end of the heel piece, to extend the range according to boot width. This means that the front bolt will then not go through the heel piece.