Hi Mark, havent' talked with you for a while. Hope all going well. Regarding FL: Personal preference. From testing I did at Guadalupe Isl. years back, seemed to me that 3' was all that mattered to skittish tuna. I typically run 12-25' depending upon the rig used, for bait fishing. But, I've also made up longer wind-ons from a 25 yard coil of FL for fishing bait for very skittish fish on a casting set up. For iron I typically don't run FL lines. But, insecurity and lack of response by fish can change that perspective... Best place for questions like this is not here, please make use of our website, you can post message on the CharkBoard or send direct email.
Braid has minimal stretch and diameter, I usually only use about 6 to 15 ft of leader depending on my application. If you get broke off and lose your leader, it's not a huge loss. I once lost 20ft of 200lb flouro leader and that was a pricey lesson on knots.
Thanks! Your answer is awaiting moderation.