I have found the larger KY have been quite fussy this year at the diversion. hence the fluoro. also fishing that weight leader you run the risk of snapping a rod tip should your drag stutter or you get a tip wrap. I also use the same weight fluoro on my spin set up and seem to have more success than guys using regular mono. I use 6lb fireline tied into a double with a spider hitch and then a 5 turn surgeons knot to connect the fluoro. Each to his own however.
Did a quick count up and have landed just shy of 170 KY since october last year, kept around 25 fish, nearly all smoked and distributed to friends and family. Fly generally outfished spinner and largest KY weighed in at 3.75KG.