Adding a flasher?

Have a 2015 P4. Rear Humminbird transducer in bilge went bad and thinking about adding a Vexilar flasher in the dash sinc e I have to epoxy a new puck anyway. Run a lot of shallow water and think the flasher would be handier for figuring out whether or not I can come off plane safely? Side image ducer is on JP so no reading on plane without the second one in the bilge. Figure on putting the flasher in the current speedometer location since I dont even look at it and it is nonfunctional most of the time anyway. Has anyone done the same? If so, will the Vexilar FL-10 fit in the speedometer hole without alteration? Anyone have any pics? I know I have to add a smaller hole nearby for the switch/fader.