Mcintosh C220 pre

I purchased a C220 yesterday to run my MC352 and have a question or two. How do you burn this unit in properly? Do I leave it on with a CD signal feeding it for a few days? Can I leave my power amp off? What can I expect in terms of sound when it is broken in? Will there be more detail, better imaging etc??? Also should I have some spare tubes around? If so, which tubes do you recommend that could add a bit of upper mid detail? (I have read the C220 can be a little lean in dealing with those frequencies)

I look forward to any opinions!!!
Congrats on your purchase. On my C2200 it seemed like after just 10 hrs it was nice and then it just gets a little better and better. I wouldn't think about rolling tubes until you've broken it in and got acquainted with its sound "in your room with your speakers", then ask for some advice one what you want to enhance. Do you have a tuner you could use instead of the CD?
Definately wait until you know what you have before tube rolling. You will stagger around aimlessly otherwise. There is no rush - only time to learn. Take it easy and enjoy your excellent preamp.

I have no tuner at this time.
I had a 1 week trial on a Cary slp2002 and found it much more detailed than the 220. On the other hand I found the 220 to have MUCH better imaging and allowed more flexibility in speaker placement. Long story short, imaging, fully functioning remote, auto biasing tubes and Mc-MC synergy were the deciding factors in my decision. I will wait for breakin, time will tell, it may open up nicely.
Another thing I must consider is my speakers (Tyler PD80s). I am thinking of getting into something a little more refined.
Anyway I am happy with the purchase and believe I made the right choice.

Thanks for the advice everyone and have a great day!
you made a great choice!!!!!!!!!!!....just settle into what you have and your going to be amazed at how good that piece is....i'm sure your already smiling