Mounting 2nd and 3rd amp in Malibu

I have a 2006 Wakesetter that I want to add two more amps to. There is currently one amp mounted (kicker zx700.5). This amp powers one 12 inch sub under the dash and all the in-boat speakers (3 pairs of speakers in the boat and 1 pair of tower speakers). The current tower speakers are the exact same as the in-boat speakers but I have ordered a pair of Wet Sounds pro 60x speakers to replace these. I already have two more kicker amps (kicker zx350.4 and zx 550.2) that I previously had in my Tahoe but since getting a new car they have been sitting in my garage unused. I would like to use the 350.4 to power the pro 60x speakers. This is my main priority for this project.

In addition, I am considering installing the zx 550.2 and two more 12 inch subs that I already have. This is not a big priority, just thought it would be nice to get some use out of the amp and subs rather then leave them sitting in my garage. The subs are the exact same as the current sub under the dash.

Lastly, I may be ordering new in-boat speakers to replace the current ones. The current speakers came in the boat when it was purchased in 2006. They are Kicker DS60 6.5 coaxial car speakers (). If I order new in boat speakers they will be Wet Sounds xs-65 (3 pair) and they would be powered by the current zx 700.5.

My main project right now is getting the zx 350.4 mounted as soon as possible so that I can power my new tower speakers when they come in on Thursday or Friday. Here are some pictures of my current set up. What recommendations do you have for mounting the amps on the hull side?