I use both Bay 60 plus 67mm, 72mm and 76mm glass filters, as well as 75mm x 75 mm KODAK gels and would use the square polymer Cokin, etc gilters filters, if I find adapters and other filters for them.
I should add, had I the right Series size filters for this larger format, I would us them as well, as needed.
Focus on Bay 60 bay 70 filters and 67, 72 76mm round glass filters, in GOOD brands will get you where you need to go.
Kodak gels would be my next choice and I carry a good set with both the adjustable pro shade and a third maker 75mm gel filter holder, which serves for other camera's/lens sizes.
If you've got it, and know how to use it, then it does no mater which of all the options works, so long as you use them and get the shot.
IMO.