I'd like to give you some tips on shaping your fingernails and what to do with your fingernails if you decide to use your fingernails.
If you don't use your fingernails, then you want to trim your fingernails back far enough that they're not catching on the strings. You have to remember that you want to go for a good tone. So if you have sharp edges on your fingernails they catch the string and it gives it not a nice round fat sound. The sound that you want is something like this [plays a note] as opposed to a clicking sound [plays a note]. So what I do is, I use 50/50, half flesh of my fingertips, and then a little bit of fingernail catches the string to give it some tone.
But I file my fingers down a certain shape and then I use two different grits of sandpaper. Start off with 1000 grit sandpaper, which is really fine, and I try to get all the sharp edges off, and then go super fine with 2000 grit sandpaper, which is just about as fine of sandpaper as they use to polish diamonds with almost. And that creates a very very smooth surface so that my finger rolls off of the string. And that way, if you think of your fingers as a pick, a pick is smooth and it rolls off the strings so that's what you want to create with your fingers.
As far as shaping your fingernails, I would experiment with what works for you, because everybody's fingers are shaped differently and everyone's fingernails grow in a different shape so experiment and see what works for you.
Now as far as what kind of guitar to play finger style on, basically you can play finger style guitar on any kind of a guitar. I have an electric guitar here that I play. This is my main guitar that I play gigs with, but I also have a nylon string guitar that you can play finger style of, sort of like classical tradition, or just any steel string acoustic guitar works good. Any guitar basically you can play finger style.