I am trying to decide on if I should buy a runecrafting premium script or pay someone to make me a private runecrafting script. What would be the pro's n cons to this? Money isn't a issue by the way.

Private scripts definately cost alot more but if you have certain features you want it the best way to get a script tailored to you rather than the more AIO approach of premium ones

Do the current sdn scripts meet all your needs? 

You need to know that certain skills has a higher banrate over the others. Since money is not an issue, why not try the premium version one and a private script on another. It's all about experimenting. Everyone has different opinions

My opinion, private scripts tailored to your playing ways is the best. It simulates the way you would play. Maybe you play the same as a few hundred or so. But compared to a script that could be used by thousands using the same method. 
Just my 2 cents.

be prepared to shell out $100-500 if you request a private rc script