Finding the right tube preamp (input values) for Mccormack DNA

Forgive me but how do I determine the input sensitivity on any particular tube preamp? 

I have tried to figure it out some manufactures are easy and label it but some have a lot of values and with my limited knowledge of values and current specs I find it hard to figure out which is a good match.

I have a Mccormack DNA-1 Deluxe and am looking to add a tube pre. I have seen the likes of Audible Illusions, Conrad Johnson, BAT, and others who are good matches but I would like to possibly see about modern gear for a good match. Like Jolida, Rogue and Odyssey to name a few. 

What are the specs I am looking for to see if they are a good match? I have read the Mccormack has input value of 10v.


Thanks @yogiboy ....I have read that some tube preamps would have too much gain for the Mccormacks due to the high input...... hmmm

@gdnrbob I will be in contact with him this week. Thanks,

You must take the preamp gain into consideration. In most cases it's not an issue, but CJ preamps have high gain. Find the gain of the actual preamp you're interested in and ask Steve McCormick.

@photodusty -- I think the problem with tube preamps is more with Steve's amps with his higher-level revisions (A, Gold, Platinum, etc.) rather than the stock or Deluxe models.  If memory serves, input impedance on models with certain revisions was quite a bit lower than 100 kOhms, but this may vary by model and revision level.  As mentioned earlier, you should be fine in most cases with your amp. 
@soix I believe you are mistaken.  I asked Steve Mc about input impedance and was told that it remains 100k after his SMc Audio upgrades.
See, now even more confusing. 

So when looking at a preamp, what values what am I looking for?...some say 10v some say 100K some say 28db volume.....etc....