I think with 1 veteran and 4 RAF accounts, you will always end up with one account that cannot receive granted levels.

If you're leveling characters on accounts 1-5, accounts 2-5 are earning levels for 1-4. But then who is working for Account #5?

To not waste free levels, it sounds like you would have to have 6 RAF accounts. Leveling up accounts 2-6 would then be earning levels for accounts 1-5. Then you level accounts 1-5 to 30, and grant them to 60.

You could then transfer the character on account 1 to account 6, and deactivate it account 1.

That's what I would have done but someone else may have a better way.