Yes I use #17 test for my harnesses and spoon harnesses and my trolling line on my rods. Over the years there have been too many "fish of a life time" or good tourney fish lost due to folks not playing the fish right and just flat out over stretching #10 and #12 test mono. I don't troll with braid anymore. One of my fishin buddy's has always used #17 and he catches walleye to big bullets on the #17 so quite a few years ago I switched over and have not had a problem at all. #17 lays out straighter than #10 or #12 mono for harnesses ending up with hardly ever getting a twisted up mess like happens at times with the lighter mono. As far as spoon color, yes like everything else it can make a big difference. Size spoon harness I have not noticed that much of a difference. I have spoon harnesses from my handlining spoons to the big 4 inch spoons I have converted and they all work. Color seems more important. Like I mentioned I'm sure I have more than 50 or 60 spoon harnesses made up. Another one of my fishin partners who is hooked on the spoon harnesses just keeps his box of spoons with the treble hooks removed and ties up the harnesses end with a snap swivel on each one and just attaches the hooks to what ever spoon he decides to use. He is still getting more than 85% of his everyday on the spoon harness over regular harness( some days it's 100%). He's lucky as he gets to fish when ever he wants unlike a lot of us who have to still work. I prefer to pull meat than run regular spoons. Just my preference.