Im trying to hook up 2 hds units to one structure scan. First question. I want to have a transducer on each unit. All the lowrance diagrams only show one transducer. Can i hook up one to each unit? Second question. I was planning on tying all the yellow wake up wires together do i need a switch inline? Last question the front hds unit will be hooked up to a terrova trolling motor with the transducer in the trolling motor what transducer do i use in the hds program? Thanks for any info in advance.