So your question about mounting a helix 7. I used the 1.5" ram mount with a 9" arm. I fish in ND, I have zero problem with it holding. The balls have a rubber like coating on them. When you tighten it down, it really hold. If you want to see a really SERIOUS mount, go look at the website, Balzout.com . They manufacture the from aluminum and they are a thing of beauty, exepensive, but really impressive!!