The Big Stopper has to be light sealed for it to work. Even light through the viewfinder on a long exposure will cause flare and ruin the image. The petal hood on the Nikon lens makes light sealing impossible and therfore a long exposure filter just will not work on that lens, regardless of holder system.

The polariser is a slightly different story, as you can get 150mm polarisers which are used in the movie industry. Because of the size, these are made in 4mm glass and cannot be made in our usual 2mm thickness.
These 4mm polarisers are extremely expensive, heavy and would be awkward to use in the SW system as you would have to adapt the holder to take 4mm filters – our advice is that you should not use one of these filters with the big holder, and we do not recommend it.

Putting any sort of filter onto an extreme lens of this sort is always tricky, and it is impossible to offer anything as flexible as our normal system in this large size.