Fact: a group of experienced film photographers can view a large, random body of images and not correctly guess the film that was used 95% of the time. Unless you’re viewing a photograph that has
very distinctive properties (such as Kodak HIE), by the time the photographer has finished processing the image for presentation - be it a print or a digital image online - it’s not going to be possible to reliably identify the film used.
So, you’ve come to a sensible conclusion on your own. Yes, grain characteristics will tell you something about the film's speed (and negative format) but that won’t be a reliable indicator of film type. Most films can be used to make pretty much any kind of image the photographer wants. Some films are better adapted to making certain kinds of images. For example, people often choose Neopan Acros for night photography because it has very good reciprocity characteristics. The bottom line is that modern films are all - for the most part - excellent materials to work with and in the hands of someone who knows how to handle them, they will deliver excellent images. So choose a film that works
for the way you want to work and learn its characteristics and handling requirements: expose lots of film, spend some time doing tests (over and underexposure, increase/decrease development times, etc).
As an aside - speaking of over/underexposure, I recently took a closer look at Tri-X and bracketed a roll of it (120 format) with the maximum overexposure going all the way up to 2.5 stops OVER box speed.
This is the finished image from the negative that received 2.5 stops exposure over box speed, and
this is the image from the negative that was rated at my normal exposure rating of 200 ASA. The 2.5 over negative was quite dense, but I had no trouble making a good image from it. I wasn't exactly surprised, but this was a good reminder that modern films are far more capable and flexible than they were 50+ years ago.
If I were to make a reasonable recommendation for you, I’d say: try any film you want to try, avoid playing around with esoteric developers and development techniques, stick to basics first and make observations about your results (take notes!) and once you feel you understand the essential traits of any given film, go ahead and poke around the outer edges of what’s possible. I also recommend getting a copy of Henry Horenstein’s
“Beyond Basic Photography” - it’s a rich, well written manual for those who want more out of their B&W film work and are eager to explore film media. Copies can be had on fleabay for about five bucks, shipping included. (Used, of course)
And since you’re clearly interested in the chemistry of film/darkroom processes, “The Film Developing Cookbook” by Troop and Anchell is an excellent book to have. It is written in a style that is accessible to both novices and seasoned pros, and is a fantastic manual to teach yourself all about film chemistry.
About sourcing darkroom chemistry: you
can buy very small amounts of chemicals from places like Formulary, but it’s a false economy - 100 grams of Metol isn’t that much, and having it on hand will enable you to make up a few simple developers at home. I’d recommend buying what you need
to make D-76 and maybe
Mytol (home brew Xtol. Recipe #2 is generally accepted as "the right one", but none of the three referenced on that page is "wrong") so that you’ll have good reason to have multiple chemicals on hand. 10 grams of Metol from a supplier isn’t going to be that much cheaper than 100 grams from ArtCraft once you add a pound of sodium sulfite, and maybe some phenidone, etc.
