Speaking of the various junction knots between backer and mainlines and/or leaders, Aaron Martens published a video a few years ago about using braid as sort of a deep backer line, then an attached length of fluorocarbon well beyond his expected casting distance. The junction knot he used? Just a simple overhand knot. He said the reason was he'd never get close to the knot so he didn't bother spending any time tying a more reliable knot like a uni-to-uni. If a knot remains far enough back coiled up on the spool, it is exposed to very little tensile force.
But, he likely gets his line for free under a sponsorship and also likely replaces his fluorocarbon long leader after every day on the water. So, for Martens, it was just a matter of cutting down on time to set things up for the next day.
And, it is presentation-specific, for sure. You sure wouldn't want a big fish to spool off enough line to test that kind of junction knot!
Brad
He was backing with braid in that instance just to reduce spool weight. He often fishes braid to fluoro though with a much shorter leader.
The Tactical Bassin' boys fish braid to fluoro and use a blood not. Weird thing is . . . they'll put a 40 foot leader of fluoro on which means they are casting the joinder through the eyes going out and reeling it back through coming in.
The catch some really big fish out west so I think if you can tie a really good Blood or FG knot, it may not matter.
They tie the long leader not because they are worried about the braid spooking fish as the fish assess the bait, they worry the braid could spook fish well before the lure gets close enough to get them to feed or react. Of course, some of those lakes are really clear although I don't think Clear Lake is one of them.