Custom artboard sizes on Artboard dropdown

[kingluc]

I'm not talking about creating a new document template with a custom artboard size.

I'm looking to be able to add to the preset sizes, so when in a document I can select a specifically sized artboard we commonly use at our company.
I'd also like to remove many of the current ones, as I never use them.

Is there any kind of sysyem file I could perhaps edit to edit that default list of sizes?

I'm working on OSX, so ideal locations would be related to a Mac, but even if somebody knows this for a PC I could probabaly figure it out from a PC location.
Thanks

[Doug A Roberts]

They are tied to the document presets, but I've not yet come across evidence they can be changed.