[sdiy] dare I say - decoupling?

[Michael Ruberto]

Well we know who the decoupling experts are here, and they do shine so 
brightly. At the risk of sounding like the moron I am I must pose 2 
questions to the decoupling kings.

which is better, decoupling caps from each rail to ground, from rail to 
rail, or both?
what's the difference?

what is the air-speed velocity of an unladen swallow?

thanks in advance oh wise ones ;-)

M. A. Ruberto