Hello and thanks for your demos !
Don't be sorry. I know that it's not always easy with old machine.
I think also that Atari ST is very reliable.
I have the same issue with the vertical picture at the beginning of 20 years STE.
I spent time on Atari STe demos because next Saturday, there a retrocomputing event and I will show what an Atari STe is capable of !
I only have an old Atari SH205 but I don't use it very often because it's very noisy.
So, I use PC computers to write ST disks.
I don't have any machine with TOS 2.06
I am French and I use TOS 1.62FR
I have a TOS 2.0X on disk. Maybe I could give it a try.