I started with 10' rods ... fishing out the back of a buddy's boat. When I decided to add this method to MY fishing, I bought a 14' BnM PST rod (and still used the two 10' rods) and a couple of the 4 rod Hi-Tek holders (& 4 base plates). I've since added two 14' BnM Capps/Colman rods (which have a softer tip than a PST). Now ... I don't "spider rig", per se, but usually push jigs & cranks. I do well to keep up with the 3-4 rods, so I've never seen the need to purchase more long rods or use both rod holders up front.

While I do prefer to cast ... having this minimal setup does offer me more choices in the ways I can fish. And it has produced fish when casting wasn't productive.

I have a 42# thrust 5spd 12v TM that I ran on one series 27 deep cycle marine battery ... and it worked well for moving around & casting and such, but would only give me 4hrs of pushing jigs at any appreciable speed. I've since gone to a series 29 battery and it seems to hold up much better. If I wired two of them in parallel, I wouldn't expect any problems with pushing jigs @ 0.8mph for the whole day ... let alone spider rigging @ 0.2-0.5mph.

There are a host of different styles of rod holder, and most owners will tell you "theirs" is the best. Take a look at Hi-Tek, Driftmaster, Bee Ready, Cumberland Crappie 360, Spyderlock, or even the single rod rod holders (if you don't mind drilling a lot of holes in your boat) ... and decide which one looks to have all the features YOU would need. And if you suffer sticker shock when you look at their prices ... keep your eyes on the Personal Classifieds Forum (that's where I bought mine), as there are deals to be had, not only on rod holders, but long rods as well.