I have two recommendations.
First recommendation - pick up a single sheet of 1500 grit wet / dry sandpaper. That one sheet will last you many, many years. Cut off a small rectangle about 3" x 2". This small rectangle will last a very long time. The sand paper is very flexible- so you will be able to smooth the underside of your nails. I was taught this technique at the University many years ago (1978).
Second recommendation - pick up a copy of "Pumping Nylon" by Scott Tennant. He describes how everybody has unique nail shapes, etc. He lists the several common nail shapes, and his recommendations on how to shape your nails- ( based on how your nails naturally grow). His description is by far the most educational I've come across. (my opinion). He includes drawings which help the reader understand exactly what's being discussed.
Developing your "perfect--ish" nail shape is a trial by error method. And-your nails are constantly changing - so be prepared to experiment a little.
As you know, an improper nail shape may cause your nail to "snag" or cause extra resistance on the string. (Never a good thing).
Good luck, Stephen
Doesn't everybody want to play guitar?