Confused about Screen-size and Fullscreen scaling. (Solved)

[Zathura]

New here, and with what is probably a dumb question. I tried a general search in this forum for screen size, but returned a lot of technical issues that dealt with any number of screen settings that I know diddly about.

I'm just curious what would be a good resolution to set at the beginning of a project if I want it to be able to switch to fullscreen seamlessly on a wide-format monitor. For instance, the practice project I have now, which is at the default 800 x 600 gets black edges on the sides when I set it to fullscreen, whereas all the VN's I've downloaded to play are able to scale seamlessly and fill the edges of a 16:9 (or comparable) screen, despite having what appears to be an 800 x 600 windowed size upon initial startup.

Is this something to do with the starting resolution, or is it something more in-depth? Are there some things I should keep in mind as far as art assets (say for custom text-boxes) if I intended to include this kind of functionality?

Huge thanks to anyone who takes the time to respond. I'm really trying to buckle down and at least get the basics of Ren'Py, and would love to challenge myself to participate in NaNoReNo next month (ambitious of me, admittedly, lol).

[PyTom]

I'd suggest using 1280x720 for new projects. (That will be the default in Ren'Py 7.0.)

[Zathura]

Alright, that's one way to fix it, I suppose. Thank you.

I was hoping I was just missing an editable option, or could insert a couple lines of code to get the screen to scale seamlessly, but can't seem to find what I'm looking for. I guess I'll mark this as solved, then.