Love using PowerPro on my downrigger rods - zero stretch, low drag, can't wear it out. RT, on the spectra/ mono joint, I was never satisfied with any knots (always balling up) and your mini swivel idea is good but I have taken to splicing in an 18" piece of old style dacron line between the spectra and the leader. The spectra knots up nicely with the dacron and the dacron ties well with the mono. Also, when trolling, the dacron piece works better than the spectra or mono in the rigger release clip.