FF/Transducer question

[2ndCurse]

After alot of research and frustration, I have decided to bring my old Furuno FCV667 out of retirement. I looked for a comparable but smaller unit at a reasonable price. I just didn't see anything that would give me the performance I was used to and still be affordable.
Has anyone mounted one of these on a V20? Where? Pics? For those not familiar, these are big units. I am thinking about hanging it under the steering wheel,just to the left. I will probably bang my knee on it, but I need to move the seat back a few inches anyway.
What about the transducer? I have a thruhull. I could use it to shoot thru the hull, as long as the hull isn't cored. I'm 99% sure it's solid. Is it? Or I could drill. If so, where? I have read complaints about ff's not reading at higher speeds on the V20.
I had this unit mounted on my 20' Hydrasports. I built a shelf on the console so the monitor would fit and mounted the transducer right on the keel. It read clearly into the 40's.
Any input is appreciated. Thanks