I have tested CD-Rs on two different recorders at various recording speeds.
I would recommend 4x as this produces the lowest BLER for most of the discs
tested. Discs these days are not optimized for low speed writing such as
Canadian Conservation Institute
I make my CDs at 2 or 4x. I note those presently aalable go up 56x or so.
Is there any reason these won't perform well when recorded more slowly? I
can't imagine why they wouldn't but better safe...