[musico]

Hi all,
 
I am wondering about buying tubes for a Little Dot Mk VI, and read about people getting 'matched pairs', and was wondering what this means and why?
 
The Mk VI needs 4 power and 2 driver tubes, and was wondering...
 
Does this mean that for the 4 power tubes, that a matched quad is needed? Or will 2 matched pairs do for the power tubes (and put them symmetrically so to speak)?
 
Anything else to look for when buying tubes?
 
Thanks for any input!