I'm surprised to see so many use a presoak as I've never found it necessary. After playing around with a variety of developers ranging from ID-68 to FX-1 to Parodinal to Ansco 47, I've settled on good old D-76, which I run replenished (mix up a gallon of developer and a liter at a time of replenisher and replenish until it's had a gallon total of replenisher added, then mix a new batch.) I get remarkably consistent results and drop-dead gorgeous negatives from Plus-x, Acros, Neopan 400, Tri-x, HP5+, Fomapan, Tmax 100, Delta 100, FP4+, PanF, pretty much anything I throw at it. I shoot at box speed and develop for the recommended time (adjusted for the normal ambient room temp here in Florida of 76-78F.)
Here's my standard technique:
Pour developer in tank (no presoak) and agitate for 30 sec, then 5sec (3 inversions with a "twist") every min
SB-1 stop bath for 30 sec with agitation
Fix in Hypam at standard dilution for twice clearing time
Water rinse (fill tank with water and agitate for 1 min)
HCA-1 for 1 min with agitation
Fill tank with water every min for 10-15 min, agitate first and last 10 sec of each min
Final rinse in water with 2 drops/pint of Edwal LFN for 1 min
Hang up to dry
I mix my D-76, replenisher, stop bath and HCA from scratch from the Darkroom Cookbook (checked against earlier works for accuracy) and the rest are commercial packages. All the water I use is from my reverse osmosis system, which includes carbon and sediment filters. No problems with spotting, never see streaks or other artifacts from agitation. To determine clearing time for fixing, I save leaders from 35mm and drop them into a beaker of fixer when I'm processing the film. I also keep track of how many rolls have been through the fixer and mix fresh before the clearing time gets to 3 min with something like Tri-X or Foma. This is all good for 35mm and 120, and I'll be testing it soon with 4x5. It may be a "boring, normal" process, but it works for me.
Maybe I should note that I shoot manual (match-needle for most 35mm and hand-held meter -- Luna Pro or Minolta Autometer IV -- for some 35mm and most all 120) and I expose for the scene, which avoids a lot of the need to compensate in development for exposure compromises. The only time I use autoexposure is for color negs, and even then I use the compensation when needed.
Ulysses