Migrating Products.Maps

I have been asked to (maybe) re-theme a Plone 4 site.
I would prefer to upgrade it to since theming in Plone 5 is easier.

The main problem is that the site has hundreds of Location objects (Products.Maps). I assume these needs to be migrated to something else.
Is this 'doable' in a sane way? Would it be possible to use /@@custom_migration to map the fields to another content type . Maybe using collective.geo ?

Any suggestions welcome.

OK… I have found out how to convert 'old Maps coordinates' to 'Collective.geo' cordinates.

Does anyone know how I 'write to the collective.geo.bahavior field' ( I assume it should be stored in 'coordinates'