I'm practising sight-reading using https://sightreading.training/ which randomly generates notes for practice.
If I'm practising in the key of C Major, should I stick to C Major scale fingering/hand positions? Or is it okay to mix it up?
I find if I stick to the hand positions in the scale then I can find the notes very quickly without looking because I know which finger they are under based on my current hand position.
But I also find that there are patterns that are more difficult to play by forcing myself to stick to scale fingering. For example, A-D-A-E requires me to cross over my thumb for every note.
Whereas if I moved my thumb to A it would be much easier to play but of course I can no longer rely on my hands being in one of the two C Major scale positions.
Is there a correct method, or is it just a matter of finding what's comfortable?
Edit: To be clear I'm not asking if I should stick to scale fingering religiously, More if I should be using the hand positions (1 on C or F) primarily and veering with individual fingers when necessary, or if they're just a crutch and I should just let go of the scale hand positions entirely unless I'm actually playing part of a scale.
Note: I realize this app isn't ideal/perfect because the notes are scrolling and it isn't really music/rhythmical but this question still applies to any other method