[rormeister]

I can't answer the Sunpak question, but will say Cokin is brutally hard to find these days. I've ended up with the Cokin P holders and Lee filters, which are more expensive but I'm told better quality than the Cokin. I've used the ND grads with my Sigma 10-20 with vignetting at the wide end even with the single slot holder (intended for the wider end).