[BobbyK]

"Larger line on bottom"
I've never heard if it makes a difference to be truthfull.
Yes,it's from the output of the compressor.

The hose sizes-I believe it's just an industry standard thing.
Like the #12 ia about a 1/2" i.d tube,#10 is something like 5/16",#8 is 3/8" etc.

the compreson fittings are on the market so they must work but for how long is the question.Our trucks are not the smoothest running vehicles out there and a compression fitting will prob. fail eventually.

If you want to splice in a tube so you can reuse the fatory "o" ring ends I'd get it tig'd together or aluminium brazed together.I'm going to try my hand at aluminium brazing some lines once I'm off vacation and back to work.

"Edit"

I've since learned the larger line from the compressor (high pressure vapor line)should be connected to the top of the condenser.
As it cools going through the condenser it turns into high pressure liquid,then into the into the receiver/dryer and then off to the FOT where it gets metered into the Evap. Core.