Noob questions on monitor/headphone calibration

Hello,
 
I'm calibrating my monitors according to Bob Katz's K-20 system. I don't see myself as an audio pro, neither am I aiming to become one, but I figure I might as well do the right things. I know how important it is in the photo/graphic industry to have calibrated monitors, in order to cooperate on a project with others and be sure we are all on the same page.
 
In order to reach 83 dB SPL at 0 dBFS, I sent a test pink noise signal -20 dBFS (downloaded from digido.com) on the right speaker, adjusting volume until getting 83 - 3 = 80 dB, then I did the same for the left speaker.
In total getting 83 dB when both  speakers are active.
This is the correct way right ?
 
Not having a SPL meter I'm using a condenser mic on a second audio interface. Or do I absolutely need to purchase one?
 
Listening on such calibrated monitors to non compressed 3 Cities from Bombay Dub Orchestra, one of the album Katz recommended for testing headphones on innerfidelity.com, I came to the conclusion that it was quite louder than what I am used to, and that there is no way I'll be able to listen to music for a few hours per day in my flat without neighbours complaining. Quite the same with the test tracks of HDTracks, which have bigger dynamics.
 
So I calibrated my closed headphones (AT M50) in almost the same way, i.e I put the condenser mic in the center of the headphone and adjusted the volume of the pink noise -20 dDBFS signal until I measured 83 dB (on a second audio interface. This is where I discovered, btw, that Sonar could drive only one audio interface at a time. No idea if other DAWs have the same limitation).
 
Unsurprisingly, so calibrated is also quite louder than what I'm used to hear. I called myself on my smartphone and couldn't hear the call. As a really super basic check test, do you find it normal not to hear a smartphone ringing with a K-20 calibrated closed headphone ?
 
Last, I hadn't much time so far to play with Sonar Platinum, but it seems there isn't much in the way of meter customization, for example presets for K-12, K14, K-20, or to define boundary values for red, yellow and green.
 
Are you using meter plugings or are you using the standard Sonar ones ?
 
 
Cheers,
Cedric
 

If you're worried that your monitors are to loud and will annoy your neighbours, move them closer so you can turn them down but still get the same 83db at your listening position.