ARC gear: Setting gain between Phono/Pre/Amp

I have a SET amp with an att. pod to adjust gain. I found that the Ref phono sounds about 6db louder straight into the amp than through the LS5mkii at the 12 o'clock position (+12db gain). By switching the LS5 gain to the +30db position I can match the Phono's direct connect volume at the 9:30 to 10:00 position. Having only learnt that the Pre was attenuating the Phono's output I would like to know, is it desirable to have the Pre setup so that it's at least at the same vol or louder than direct connect, or is it the norm to attenuate?
The volume control on most preamps are not perfectly linear. And, many preamps have the electronics 'tweaked' to give the most natural, best performance at the 'middle position' (12:00 o'clock).
So, I would say without hearing it, that the best technical preamp volume control position (if the gain can be changed) is the 12:00 o'clock position. (Really the 11:00 to 1:00 o'clock area)
(MY Audio Research SP-15 has a rotary switch that cuts output in steps right next to the volume control, and the best positioning allows the volume to be used around the 'best' part: 12:00)
Reality... (best sound) may differ from this 'educated guess'.