We have a 2013 Kenworth T800 that only has one stack on it, and we would like to install the second one. Thinking of putting 7"s on it while we are at it. Has anyone done anything similar to this. Any suggestions on any kits to buy? I checked with several sellers, but did not really find anything I thought was a great fit. We have another T800 that has both stacks on, would I be best to try to copy the system on that one? Or would I be better trying to copy an older style elbow design instead?