Re: new storm doors for an old house
As with the primary doors, the main air leakage with storms will be where the two doors meet. The astagal is very problematic to weatherstrip. I don't know if you have rabetted doors or an applied astragal. The best weatherstrip I have found for these is the interlocking metal type. They give a good seal but add no friction (if perfectly installed an maintained). You also need to take care of the bolts that keep the fixed door in place, they should hold the door steady without any play.
A pair of custom double storms is going to cost "a pretty penny" as they say.
Remove not the ancient landmark, which your fathers have set.