Sony F828 ND filter questions

[dwdallam]

I need a couple ND filters for my Sony F828. I bought a Kenco (which is the Japanese name for Hoya) Polarizer that has an equvalent ND of 1 2/3 stop. So what should I get?

(1) Single coat or multicoat?
(2) The new thin ones w/o the front thread, or regular?
(3) Which range, given my 1 2/3 polarizer?
(4) What brand?
(5) Ultimately I want to be able to use my longer shutter speeds with my maximum F8.0 aperture in most light situation at ISO 64.

Thanks again.