Why would you choose track geometry for that range of ride lengths. I don't know track bikes, but I wouldn't personally choose a 75 degree seat tube for the kind of riding you are proposing. Probably not too far off what a tri bike would be (another style of riding I don't know) So it may work ok for a given posture.

I design seat tube angles from my personal preference combined with the specifics of the seat post, rear wheel, and seat needs I have.

I design the front angles from the handling and fork type I will be using. The top tube and downtube relate to my torso size, and features of the bike type. The rear stays are usually long on my bike but different uses will dictate. The design just fills itself in. Ideally you should have on hand as many of the parts as possible, so that specific numbers you assign relate to the real world as much as possible. It is alluring to only spend money on the parts when the frame has been built, but unless you have done the same bike frame before, it makes more sense to actually have the parts on hand.