hmmm, I never mate. Just whopped the tape in and off we went. Never liked Dolby B or C and never tried the new one (S I think) I prefered the hiss and the treble.
Common myth about Dolby, treble loss, although a lot of badly setup machines didn't help.
The idea, at least for quality recording, was to chose a good tape and get a tech (c'est moir!) to set the bias.
Regarding jodrelling about with levels, why? Once you knew the peak level off the vinyl deck you were set, the dynamic range of properly setup TDK AD.SA, BASF, Maxell UX etc was easily the equal of the black stuff, which of course were themselves cut from at best 2nd generation tape.
It is of course ironic that the digital "revolution" came just a bit late to save cassette. That Denon I had was auto setup. You put in any tape and after 30seconds or so it was optimally biased.In fact with Dolby HX you did not really need Dolby B at all for dubbing disc or radio. You had to watch tho' that the levels HX allowed did not crack the replay amps on some lesser, mostly ICE machines.