Well this thread is growing into quite the discussion, many thanks to all for the input.
I was going to ask which line was the supply and return for the cooler (more on that) but thanks to Kevin's post re Grady Clay's diagram , I already have my answer.
So time for some pictures of the "plan". You can see the cooler, one of the 12 AN 90 elbows, the 12 AN hose (good for 350 psi) and the adapter (work in progress) to attach the custom hose to the hard lines. What I did was buy one stock cooler flex line, cut off the ferules (much tougher than expected) and now had the barb and female fitting to hard line in hand. The barb was too large for the 12AN hose (by 2mm) so I cut it off and you can see the new barb in picture two. It is a hydraulic hose style that will be welded to the female fitting cut off from the cooler hose. Once I determine the final length, I will have it crimped on at the hydraulic shop. The reason I wanted to know which was the feed and return lines is I want the fan thermostat (brass fitting on the lower right hand side) to be on the exit of the cooler not the infeed side. One feature I like on this cooler is a drain so if you are really OCD, you can drain the cooler during an oil change.
I'll post further pictures once I get it all together, the season is soon drawing to a end so it will be the time to dive into the many planned projects during the downtime.
