Do 4x4 filters work in the Cokin P system?
 

I last used Cokin for grads and polarisation as an enthusiastic photography student, back when we used a Darkroom rather than Adobe Lightroom.

I've now got a matte box and a bunch of 4x4 filters, but the 'faff' factor of it all is really off-putting in my Run & Gun mode (Genus and its drop-in mounts). "If only it was as easy and quick as my old Cokin system" I thought.

So has anyone tried stuffing a Tiffen or Formatt 4x4 filter into a Cokin P mount? Or are the Cokins thinner?