Hello Markus, sorry to bother you again, but I just found out that nibconv does not honour the speed testing.
I wanted to convert a D64 in a G64 but with longer tracks.
nibconv -C295 disk1.d64 disk1.g64
the line above should create a g64 containing the D64 data but in longer tracks.
Instead, analyzing the g64 with nibscan, shows that the track lengths are the same as without the parameter.
Could you fix that?