Goode v Goode is the seminal case for dealing with such matters, so any argument involving equal shared parental responsibility and the child’s best interests will often cite this case. 
As the Children get older their own views will be considered by the Court so the argument will be what is important, significant and valuable to the child, therefore any arguments ought to be Child focussed and what is in their best interests. 
As meaningful is a qualitative adjective, not strictly a quantitative one it lends to the argument that significant and meaningful time is about quality time as much as it is quantity and this is why the wishes expressed by the Children become more and more valueable as they get older.  
This is why the Court may take the “present relationship approach”, which involves making findings as to the nature of the child’s relationship with both of the child’s parents as at the date of the hearing, findings which are ultimately reflected in the orders, may also be relevant.
Disclaimer.
Any such arguments really must be discussed with your lawyer as we are getting into complex areas of law that you would not want to try argue without legal advice and for the record none of the above should be construed as legal advice, it is purely legal information extracted from case law for you to consider talking to your lawyer about.