Fence construction

[Issec]

I plan to build a fence around our house myself, and a few questions have come up. I am thinking of building a fence with 45x45 vertical studs, 180 cm high, with 1 cm spacing and cut-off tops at 45°.

I will use ground screws, and I have concluded that 95x95 studs are required, but is 180 cm spacing okay or should it be shorter? What type of ground screw is appropriate?

What kind of bearer beams are smartest? I am considering either beams that I attach between the posts with an angle bracket, or some thinner beam that I screw onto the outside of the posts. In the latter option, is it worthwhile to carve out grooves in each post or is it enough to just screw? How many "levels" are needed?

I would like to stain the fence brown, and I am thinking either to build the entire fence with pressure-treated wood, and stain the exterior after a season, ignoring trying to reach between the slats. Do you think it will be noticeable if it's not painted between even though there's only 1 cm spacing? The other option is to use untreated 45x45 studs for the slats, which I stain before construction. This seems a bit more complicated but of course something I'll do if necessary!

Please share your thoughts and advice on how to do it best, and feel free to include a drawing of my plan!

Regards,
Issec