I fish my line going through the inline lead and tied to a fox no 7 quick link, my hook length has a loop tied to the swivel end that i can remove from the quick link and thread a bag on before each cast.
I don't use a leader, but have in the past, it would depend on the water you are fishing and the mainline you use, i haven't used tubing in a long time, tubing has moved on since then, i would happily use some of the tungsten tubing the is about these days, years ago it was very stiff and had no sinking properties, today's tubing is different, and if i was unsure on how to use a leader safely the tubing would be an excellent alternative.