Record Limitations on Books of Business

Hello - I am considering implementing a new Book of Business for a client who has never used BoB before.  This would involve creating a new Parent Book and 2 child Books (lets say Book A and Book .  I plan to assign all existing records to Book A and update the existing user profiles to reflect the only book they should have access to, Book A.

I have read that there are limitations on how many records a book can hold, 30,000 records per book.  My client already has circa 30,000 records which should be assigned to Book A.  I am concerned how this limitation will impact the solution and would like to understand if there is any way round this restriction.