For the loop to loop, I got tired of salvaging the cracked and broken garbage loops Rio allowed off the manufacturing floor for at least two years, possibly more. Switched back to Scientific Angler fly lines and started making my own loops for saltwater and carpwater applications. It's easy, and removes the concern about those microcracks right at the connection point.
http://flyfishingresearch.net/images/HISPANICA_LOOPS_.pdf
http://flyfishingresearch.net/images/HISPANICA_LOOPS_.pdf