Was in the local sporting goods shop today to pick out my 2nd unit for the bow to just run mapping. Currently have the helix 9 mdi+ gen3 up front to run mega 360 and was going to add a helix 9. Friend of mine who works there was helping and says the Humminbird rep tells him you can use a helix 9 mdi+ gen3 to run the mega 360 on a helix 12 mdi gen2. If that is true I can have a much larger screen for the mega 360. Plausible? Are there any drawbacks to doing this?