New Tower Speakers

I'll be installing new tower speakers on my 06 211 this w/e. I have everything, just need a couple answers to make things easier.

1. Went with several suggestions to power the new AMP to the battery and not jump it from the existing AMP.
Q - Should I/Can I go to the Perko switch, directly to the battery, or to the circuit that powers the existing AMP?

2. I will be using the Samson Sports speakers and mounts that have the RCA plug built into the tower mount. I'll be hanging them on the rear bar of the tower. Problem is the tower pivot is on the front bar/leg.
Q - How do I get the speaker wire to the back bar? Are the flat bars between the front and back bars hollow and do they have a cut-outs in them to let the wire pass through?

Thinking I may have to mount them on the front bar, but I dont want to do that.

yes go to the common of the perko switch, that way you will be pulling of both batt. i do not think that there are any holes in the tube you need to make your own. look on line for way to run the wire .