Tubes Recommendation for McIntosh Preamp

Hi,  I recently purchased an used McIntosh 2-chassis C1100 tube preamp.   So far I'm pretty happy with it.    

I'm thinking about replacing the line level stock tubes.  They are 2 12AT7 and 1 12AX7A per channel.   

I'm looking for recommendation from fellow members here.   I would like something on the warm side (definitely not bright sounding), and good solid and tight bass.   

Also I wonder if I need matching.  e.g. do I need 2 matched pairs of 12AT7, with each matched pairs for each channel.  Or do I need matched quad of 12AT7 for both channels.   Same question for the 12X7A.  Do I need them to be matched.   I don't seem to see any information available in the user manual on tube replacement.

Thanks very much in advance!