Sea gar some of heavier weights wont work well on spinning reels, but are excellent on bait casting tackle.But an interesting point about flouro. I dosn't work well on surface baits, because it sinks. I noticed that the first time i used sammys, and zara spooks. there is very little stretch, and its mostly invisible. I like to troll, there was a difference in depth achived with mono as compared to flouro, and also between flouro and braid. So now I use braid and a flouro leader for most fishing, but not for surface, then its braid. Diameter does effect depth also. But thats just my opinion. Things like this make me wish I'd stick to the KISS system { keep it simple stupid}