Phono Stage Gain Question

I have a Manley Chinook phono preamp.  I'm running a Kiseki Purple Heart cartridge.  All is driven by a Primaluna Dialgoue HP Premium into Klipsch Forte III loudspeakers.  

I have two gain settings on the Chinook.  45dB and 60dB.  By some sort of default logic I have always run things with the higher gain setting, figuring it was needed because I'm using a MC cart. 

Well, the Forte IIIs are pretty efficient so my volume pot rarely went above 9 o'clock or 10 o'clock.  But things seemed slightly congested as I turned up the volume.  Today, I moved the gain switch to 45dB.  Now, I can listen at 68-72 dB (checked with a meter) and the volume pot is at 12 o'clock.  If I want it loud I can listen up to 1 or 2 o'clock. 

My question is--  Is the a soft rule or notion that you should try to get away with the lowest amount of gain possible?  Or given the output of the cartridge should I select the highest gain (60dB) that I have? 

While my ears will ultimately be the guide, it seems like I'm caught between extremes on volume settings.  With 60dB of gain, I rarely move the pot past 9 o'clock and with 45dB I'm going to be running things nearly always at 11-12 o'clock and for louder sessions near 2 o'clock.  Does the position of attenuation matter?