In my limited stand development experience I've found the first 3-5 minutes to be kind of more crucial. I would make sure to pre-wet for a good 3 minutes, then agitate for 30 seconds, then once for 10 seconds at 3 minutes and again for 10 full seconds at 5 minutes THEN walk away for 20 minutes, then invert once and swirl (with the wrist not stick) then set down, then again at 40 minutes and then the last 3 minutes agitate again 10 seconds then sit a minute then again for 10 seconds sit another minute the. Stop Bath etc etc.
I never use the swirl stick, always full inversions, I always have uneven development with the swirl stick, always...
The above is with Rodinal 1:100 for one hour. I first did this with C-41 films am now with traditional B&W films. If you want some grain perhaps the C-41 method is something to look into. Check my threads for the C-41 cross processed in B&W thread to see examples.
Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk