I find the standard LS8000 film carrier works wonderfully if you use it properly. My workflow follows.
(1) Cut the film so it runs the length of the carrier with a tiny bit of overlap on the left and right.
(2) Insert the film and flip the upper clamp down to grab the top.
(3) Using linen gloves press down so the bottom of the film overlaps the bottom carrier region.
(4) Loosen the bottom clamp screws slightly so the bottom clamp moves up and down.
(5) Close the bottom clamp so it grabs the film and lock it.
(6) Pull down slightly on the bottom clamp to tension the film and flatten it.
(7) Tighten the locking screws so the film stays flat.
(
Zap the film with an electrostatic antistatic gun if you have one and blow the dust off with canned air.
(9) Insert the carrier and scan with software of your choice.
I get scans from 6x9 trannies that make gorgeous 30"x40" prints from this scanner.
If you can't master this, I guess you can buy the glass carrier from Nikon. The glass will degrade the scan some as you might guess.