Issue with registration with 1 free and public subscription (on membership)


I have membership set so the following subscriptions

1) Member - Free (Public)
2) Mod - Free (Private)
3) Admin - Free (Private)

I am concerned about the messaging on registration. If I use the pop-up registration then after subscribing/registering to the first tier (Member) then I am shown the option to subscribe to my two other Private subscriptions.

If I use the Original Member Form, then on completion I get the following message:

You currently have a subscription for the Members subscription. If you wish to sign up a different subscription then you can do below.

There is nothing to display, so it is not the correct message to display. I'd rather not edit the core code and change the message. Any advice on the best registration process with the above setup - so that on registration complete of the first free and public subscription I just see a 'Thanks for registration' message and/or a redirect to the homepage.