What lens(es) do you have? They determine what filter size to get.

If a bayonet 60 (CF or later) lens, a 62 mm thread filter is too small, and you would have to go for the larger 67 mm filters. That is, if you want to get thread mount filters instead of the bayonet ones.

And if you have a bayonet 50 lens, you would need an adapter to 57 mm. Not 55 or 52.

If you plan to use your filters on other, non Zeiss/Hasselblad lenses too, using an adapter to screw mount filters would be the better choice.

Heliopan and B+W are two brands of good glass filters.