On the issue of presoaking, I presoak 120 roll film for a couple of reasons. One is that, when the ambient temperature is very different from my target development temp, it allows me to adjust the temp inside the tank to something closer to what I want.

When it's 90F in the room, using a presoak of water in the low 60's prevents my developer temperature from immediately shooting up from 68 to somewhere in the 70's.