Where is it going??
I would say zero degree if you are talking tilted element.
Not sure what you are asking.
12 or 20 degree angle of the hull for where you plan to install or beam width the transducer.
I'm guessing angle of your hull.
Go to Home depot or Lowe's and but a cheap angle finder like this
Shop Swanson Tool Company Magnetic Angle Finder at Lowes.com
Thanks for the help guys I will check home depo tomorrow. First time with a question and had it solved in 10 minutes. Great site. Will post some pics of build when done