I'm not being sarcastic or anything, just trying to understand.
It is do able but is it that hard to fidget with the map setting after you go in? If I know what type of map I'm going to be working with constantly, I make one base blank map page and duplicate it as needed. Another word the map settings would have to be outside the board in the detail page area. There would have to be the following A section for the creation of the board in the detail section that would contain Map size box : (unit) by (unit) scale box : (size) by (rating - ft, meter, etc.) Grid (checkmark) enabled: Size (# ) units etc. There would be alot of stuff to work with. They have it defaulted to a general settings in the code itself so to do what you are suggesting would probably need to make a UI section for creating a board. The Dev's would know probably but implementing that would be rough.
Not sure how hard it would be to setup so that the board creator can set the default prior to creating the board.