Hi I'm about to install a 30kw Gasification boiler. I also require 2 x 1000ltr buffer tanks, I've looked at many installations and it's not clear which is the best option series or parallel. Also I'm not sure of the best pipe size between the 2 tanks, the tanks have 1 1/2" connections I was thinking of using 1" pipe work. The main first tank also heats my hot water, the second tank acts as additional storage. What would be the best draw off point for the central heating to make the best usage of the stored heat?