In reply to Mr G: Yes the 100mm filters will fit the the Lee Holder.
I am not familiar with the Hi Tech holder but this reviewer wasn't impressed
with some of the features
http://photographylife.com/reviews/hitech-100mm-modular-filter-holder
I have a Lee Holder with a Lee wide angle adapter ring which holds it closer to the lens and the slots can also be reduced to stop vignetting, not familiar with the Tokina lens