I would shoot thru, you might have to purchase the thru hull puck without temp do to space in the bilge. the ducer with no temp is a little cheaper. You will never notice the sensitivity with a thru hull. Add a temp probe to the jack plate if you have one. Several of us has always used 100% silicone and never have had one come loose. Use caution if you are going to epoxy it in. I would check the installation area at the lake before I made it permanent.