When fixing TMax film I noticed that I got uneven, and locally incomplete, fixing when processing 120 film in the 'usual' way (1st minute than 10 sec every 30 sec). SS Tanks and reels. Near-constant agitation with fixer solved the problem. I say semi-constant because my arms get tired when each hand is holding a double 120-reel tank! Of course, agitation method, type of tank and reel, temp. and all that sort of stuff are variables to take into consideration. When developing two tanks at once, I space the agitation of the developer so that I only need to agitate one tank at a time -- I can give it all my attention and it is easier on my arms.
I use Jobo Expert Drums for 5x7 and 8x10 -- so constant agitation there. The 11x14 negs are one at a time in large trays, constant agitation throughout the process.