I use 7.5 ft tapered 4x leader (RIO) to the end of which I attach and #10 or #12 barrel swivel. Immediately above the swivel I add any weight (split shot) that may be necessary. In these two pictures, I am using two small split shot because the river is running high and fast right now. The first [larger] fly – in this case a “Jumpin’ Jack Flash” is tied 12″ to 18″ below the swivel using 5x tippet. I usually tie the fly initially at 18″. When I change flies the distance gets progressively shorter. At 12″ I replace the now shortened tippet with a fresh 18″ one.
Now, to the lead fly, I tie the trailer using a 12″ length of 5x tippet. In this picture the trailing fly is the San Juan Worm.
The key is the swivel. When I get snagged and have to break free, the line always breaks below the swivel, i.e., the 5x tippet breaks before the more expensive 4x leader. And if you’re catching fish nymphing then you’re getting hung up fairly often.
There’s a huge disadvantage to this configuration. It is largely unusable on days when you want to be able to easily switch from dry flies to nymphs. I am lucky enough to have two rods, a 6 wt I use exclusively for nymphing and a 4 wt for dries.