Packages & Memberships

Me again. I have set up a 2 packages and a few custom fields. Some of the custom fields are available in only one of the packages and some custom fields available to both packages giving a budget package and a more expensive budget. I then set up a membership for those with more than one listing.
The bit I cant fathom is if someone signs up for the membership do they have access to all the custom fields? in custom fields there is no where to assign to memberships nor in memberships assign custom fields