I pretty much run what John runs. I use to run sampo #1 ss welded ring coastlock swivels and that worked fine. I think the duolock snaps provide better movement for the spoon however. Just make sure you have a power swivel where you connect the fluorocarbon leader to your mail line. Otherwise you'll get line twist. I take the split rings (non hook side obviously) off all my spoons. If I was tying direct, I'd leave them on or add them. I use a palomar knot from the fluorocarbon to the snap or swivel.
I've tried different knots with the streamers, but the rapala knot is easy to tie and seems to allow better movement.
I forgot to mention about the split ring removal, this must be very popular as most spoons you buy now from the great lakes area come with only 1 split ring for the hook, other end no hook ring.
rapala knot, on both flies and lures. i slip the rapala loop on and off the split rings on the db's and dont retie unless it looks damaged, very fast, about once or twice a year a lure will slip off on its own but its usually a defective ring and i was too lazy to change it.