[Raggles]

I am looking to upgrade to a Nortel Mega Minor torch from a Minor. I am using an EX 15 concentrator but research indicates the Mega minor functions best with tank O2 or two concentrators strung together. I would rather not string two concentrators together so asking what others experience has been.
Does anyone use a concentrator with high capacity ie a 20? If you use O2 tanks what size tanks do you use and how long do they last in terms of hours use before refill.
Any help would be appreciated.