If I set my RB fatigue settings to 0 (or 1), would it simply put in the most fresh RB or would it take them out until you hit the bottom one and then overplay that one?

I've seen converted TE's (to C) sometimes getting lined up at TE, despite not putting them there in the depth chart, and I'm just wondering how to run my backfield most optimal.

I basically have 4 guys I'd like to split time between and a 5th guy who could get touches here and there without me being annoyed. Nothing like having a QB3/RB5/KR on your team. :-)

Overrides are simpler, IMHO.

Do overrides always happen and ignore fatigue settings? Any good data to show at what point in fatigue performance drops off or is it linear?

I would really prefer never to have to use overrides if possible.

Mostly because I believe in KISS, but also because I don't really understand how they work well enough. Brxnivy's question, for example.

Overrides don't ignore fatigue.

That is true.
However...
If you wish to not use overrides, the AI will have your #1 RB in every formation and set. Only when your #1 RB is exhausted, will the fatigue settings come into play. More impactful, is the reliance upon fatigue settings discourages having the right back in the right formation.
We all know we do not want one back taking 30 carries due to diminishing returns and injuries (likely more the latter - which creates fear).
With the use of overrides, a GM can put the most effective back in place to maximize the plays , instead of rolling the dice. To answer your concerns regarding fatigue - to prevent the AI from using your #1s at every position on every play unless they are exhausted or hurt.
For example:
Let us take a look at 2 plays in the Singleback Big formation, within the 1/2/2 set.



A few things that are obvious:
1. A RB that can pass block is needed. He better be strong because he's gonna be blocking DEs.
2. The right side of the Line needs to be strong, quick off the line and rated highly in run block, and pretty darn good with pass block - as the pass play will take some time to develop.
3. Having a WR on the right side with a good run block rating is also a good idea. Sometimes the run moves more towards the edges, and a stronger, decent run blocking WR will only help.
4, That left side TE better have good ACC, STR, BRA. That right side TE better be strong, higher in ACC than spd to move with the line, and excellent run blocking.
5. The left side of the oline only needs pass block. Sub in the lower rated, but better pass blocker on the LHS (short route is on the right ;) ).

I am not going to go into anything other than surface detail. All of you know enough to connect the dots.
The reason good GMs have many plays that work for quality yards is simple: They maximize the personnel they have to increase the opportunities for yardage. Often, a GM will realize that this play, in that formation, with the personnel a GM has, that there are better choices to be had.

Furthermore, diversifying the usage of the personnel one has, to maximize the effectiveness of plays within a formation, decreases the amount of plays each player is involved in - thus decreasing fatigue and allowing a player to rest throughout the game.
My fatigue settings are never lower than 70.
My injury rates, apparently, are low.
I did not start winning championships until I started doing overs.

I know some folks are resistant to getting into yet another level of time spent. However, I have never seen a successful coach ignore the many opportunities to maximize the talent they have.
To do so is to assure failure.
I've always held that sliders are basic. Too much improbability for those demanding predictability.

With the broad range of abilities within any position that can create impact, and the ability to use overrides, I can only encourage persons to experiment with, and manipulate to their favor the personnel they have.
You do you, have fun, hope this helps, happy to go deeper in PM.