Hmmm, this all sounds so familiar.

Riverman pick about 4-6 days where the fishing will be iffy at best and have your buddies pull plugs all day even in the not so fishy parts until their arms are cramping by the time they get to the takeout. 1) By the 2nd or 3rd day they should have that boat running pretty darn straight because they will have so many reps in that they will not be concetrating on rowing anymore but on where to put the boat. 2) They will also figure out water hydraulics pretty fast once they realise they dont have to work as hard if the work with it.
3) takes a lot of oar strokes to get your arms balance and untrain the instinct to pull hard all the time which cause new rowers to do circles because one arm is stronger than the other.
4) This is just a theory since my usual partner still sits in the front of the boat saying "Hey, That looks like good water" and I never think a day will be iffy so I will row just because I would hate to waste a lot of trips again like when I learned.