Gutter replacement questions Zone 5a New England

We are going to get gutters replaced on our house (full cape, red cedar, white trim) — the front of the house may be about 40 feet wide and there is a porch, front and back, maybe about 10 feet on each side that we also want gutters for.

There is** an existing gutter that the builder put up and I had no idea that he was just putting odds and ends and the gutter is undersize so it doesn’t work and it looks like crap. I guess it works for the porch but not for the main house, which has a very steep 45° roof. But I would want the porch gutter to match that of the front of the house since it would be somewhat continuous line even though the porch is offset.

I have the name from somebody that our excellent roofer contractor recommends and I think I’m going to go with that company if it’s a reasonable price (although I don’t know what a reasonable price is).

It seems as though the issue is very clear cut: white aluminum(?) gutters (seam? Seamless?) that are sufficient in size to deal with the roof runoff from a large 45° pitched roof (standard cape house). We want the collective runoff to be deposited into an existing pipe that goes under our driveway and exits at the edge of the property, underground or maybe at the surface somewhere but out of sight.

I think we want leaf guards, but I do not know anything about them and I’ve heard that some people think they’re a pain in the neck and other people think their wonderful. Do any of you have opinions on these?

Do I need a contract? Does it have to be complicated?

One of the things I want to be sure of is that the workers will be fully insured up-to-date insurance for any injury or liability or damage cause to our property inadvertently of course.

I also do not want anybody smoking on the property. The last thing I want is somebody tossing a cigarette and causing a fire anywhere near the house or the gutters. I could ask this or should I put it in a written contract?

I hate to get all fussy with a contract, but maybe I need one. And how do I go about writing up a simple contract — just typing on a piece of paper what I want printing it out and signing it and getting the person I want to do the work to sign it with the stated amount of conditions?

Do I put a deadline for when I want the work completed? That’s hard because for the last month we’ve had rain rain, rain and more rain so in New England I don’t know how you can nail down a specific time but I could try but I don’t know how to word this exactly who or what to do. I’ve never seen a contract for gutters or similar.