My crude method for heat management:
I look for hotest spot on array with IR thermometer and make sure it is not more then 10 degree F above ambient temp after it has been running for a few hours. Max ambient temp is 80 degrees.

I know there are some pretty good ways of estimating junc temp with basic equipment. I just haven't got around to doing it.

I would like to set my test array up so I can continously monitor temp of each array. Any ideas?