BLKRCAT
75% Film
Looking for some obligatory samples. Stumbled across this. OP maybe your Pan F is too fast. Here's some Kodalith at iso 6 in Rodinal.

Many years ago a Kodak rep told me, as long as film isn't left to get extremly hot, if it is kept in it's sealed packet (MF) thats more important than keeping it in the fridge or freezer and it would last well past the sell by date.
Scanning or printing? IMO scanning sure, wet printing not so much.
Count me among those who've had poor luck with Pan-F and Rodinall (note the spelling?). Usually Rodin-all is my go-to developer for nearly any film to get adequate results. Not with Pan-F. I've had a bit better luck with HC-110 (very dilute).
I have yet to try diafine with any film. I think I'll give that 2-bath stuff a try....with Pan-F. Good idea or terrible?
You're not going to learn much about any film with two rolls. I get gorgeous results with fine grain and a full scale of tones including nice shadow detail and I'm using Rodinal.
Recommended ISO and development times and dilutions are only starting points. You need to buy 10 rolls and start testing for your own ISO and your correct development time. Everyone's technique for processing is different and people have different expectations of what they want plus how critical you are is most likely different than how critical I am.
Are you scanning or wet printing? Films are designed to wet print not scan and the results will be different. I wet print using an Ilford multigrade diffusion head. My system will give different results than a condenser enlarger and most certainly than a scanner.
If you're scanning what kind? My Imacon 848 will give different looking scans than a plustek or Epson. Using canned profiles or custom or scanning linear?
Get the idea? To get good results it's an individual thing where you need to start with recommendations and refine the exposture and process for you. My technique won't necessarily guarantee good results for you.
Two rolls won't tell you much other than you didn't do things right.
For my taste, I'm not a huge fan of FP4 although Ive tuned it in and get good results but like other films better.
Come on, be a little kind to all of us that has not been in the darkroom for a long time. It's been 20 years for me. Instead tell us witch films Rodinal is good for so we can educate from you a bit. Ok, I can google, but share your knowledge it's more fun to read.
Try Fuji acros@80 to 100, Rodinal 1:50, or 1:25 for smoother results