Welcome Eric. Long lining and spider rigging is definatly a learning process. Many different applications and techniques. We run duel rod holder T-bars on the bow, one on port and one on starboard. Straight out each side of the boat we run a 14ft rod, a 10ft rod, and a 6ft rod. That gives us 4 feet of seperation between each of the trailing fishing lines that are 30 - 40 feet long. Then you get into jig running depth which can be decided by a number of different variables, jig weight, tandom or single jigs, boat speed, line dia., length of line from rod to jig. As a reference, 6lb mono line, 30ft out, with 1 1/16oz. jig, boat running speed at .7 mph, your jig will be running about 6 to 8ft deep. I believe this is the most common practice, especially the 6lb mono. But again, there's no set how to rules and many many ppl use thier own techniques. There is actually a chart on this website someone has devised to determine jig running depth if you'd like to dig that up. Hope any of this helps & always feel free to ask, good luck this year & see ya on the water!
Like Momma always said, "There ain't nothin' worse than a messy tackle box!"