Paul,
So it's a bayonet 60 mount?
Than do not get a bayonet 60 to 62 mm adapter.
You need 67 mm filters. Such adapters are available too.
Yes, it is because the smaller ones will vignet.
Less so with longer lenss, yes. But still, you do not want to get an adapter, invest in a bunch of filters, and than find you can use them on one, longer lens only.
This issue is confounded by the designations used by Hasselblad. While 'usual' filter sizes indicate the size of the mount, Hasselblad filter sizes are named after the size of the glass in that mount.
So a Hasselblad bayonet 60 filter is the equivalent of a 67 mm threadmount filter.