So, Opus_Pocus, it IS meant to be played in the Dark Zone of the fingerboard !! Sadism is hereby combined with risk of injury?
I do have cut-off points on the A and E strings in practicing scales and arpeggios over one, two and three octaves with hopefully at least two good overlapping fingerings for each . These are the B flat on the E string and second octave G on the A string. Any notes above B flat on E become too thick and sluggish for both arco and pizz with my set-up and Bel Canto strings. This is why I call it the Dark Zone. I am also aware of my self imposed limitations as an orchestral player these days.
Cheers, everyone, and keep safe, DP