I'm considering jumping into the 7-string world and have 2 questions... 1-How do you typically tune a 7-string bass and what string gauges do you use? 2-I have found two used Conklins. One is a custom-made with maple board, ash body and koa top; the other one is a Groove Tools (regular wood recipe). What are the mayor difference between these two in sound? (the custom one seems to have a premium preamp, since it's got many knobs and switches). They are both priced really good for what they are, but I'm trying to decide which one to go for. I'm not near the sellers to try either bass. My main concern with the Groove Tools is that the fretwork won't be as good as the custom, and I expect to get really low action so I can play this monster. Thanks in advance for any input.