Spark Gap

I have built a RQ style air blast gap for my coil ....it's slightly modified 
from the actual plans so I could use some parts I had around the house but it 
functions the same way. Basically I was wondering if it would be better to 
put a long gap spacing with 
20-30psi across it where the air would be used just to cool the gap or if I 
should put a smaller gap spacing with 100-150psi across it using the air for 
actual quenching. Any suggestions?

And while I'm posting this question I might as well ask a few others, for 
instance could someone explain what K is to me? and what is Q? Thanks.

Left, left I hadda good brain but it left....