Hi nodb
First, I should say that I do "room recordings" at home, not at a professional recording studio.
You think like me in that I too positively refuse to edit my recordings! If there is a wrong note in there, so be it. I want my recordings to be 100% authentic, and I think my Audition Room audience here prefers and expects that as well.
There is a stark difference between the two processes of performing and recording. In performing, at the outset we experience to varying degrees a sense of stage fright. Once we start to play, and as the performance progresses, we increasingly gain confidence in front of our live audience.
In recording, the process works in reverse. We approach recording with a sense of high confidence; however, as we make some unexpected errors along the way, our confidence slowly erodes. And as the number of takes increases, confidence is eventually replaced by frustration. I think for most of us, it's the rare exception that we get a fine recording on the very first take.
From my own recording experience, I don't believe there is a way to prepare other than perhaps playing a couple of scales beforehand to renew dexterity and evenness. If there is a "hard nut to crack" in the piece such as a particular short cadenza, a double notes figure, a co-habitating of the hands requiring choreography, do a few careful trials first to ensure they are fully playable and solidly in place. Before turning on the recorder, especially review in your mind exactly how the opening is to be played and how it should sound. Play just the first few measures two or three times to refresh it in your mind and fingers. This is important, because the better the opening, the better the probability of attaining a good recording of the entire piece.
That notwithstanding, some sessions turn out to be grueling--period. We've all fought our way through those! Anticipate that possibility and decide beforehand a reasonable number of takes. Once you reach that number, and if no real progress, stop, as the session will clearly not be productive. It most likely indicates that the piece needs more work before attempting another recording session. Cutting it off then and there avoids more needless frustration.
Whenever I have a disappointing recording session, I listen carefully to all the outtakes. Then I eliminate those takes that obviously don't make the grade until only the least of the evils is still standing. I listen to it again noting the needed improvements. That one recording is the only one I leave on the recorder temporarily. It later serves as the benchmark to be beaten at the next recording session, and once that happens, it too is deleted in favor of the new completely acceptable recording, and hopefully the final one.
The fact is, sitting in front of two exacting stereo microphones is no less difficult in its own way than playing in a recital.