I live in Jax and boat into brackish/salt water here weekly. I have an aluminum trailer and always try to launch in a freshwater ramp, even though it means a longer trip to where I am going. The return trip through the freshwater creek is the ultimate flush. The only big problem I have had is that I am on my fourth or fifth driveshaft on my 15" midsection due to they corrode faster than the Gov spends money. I have even gone to speedy-sleeves to extend their life. Using cleaning vinegar is actually better than Salt Away and a fraction of the price. I keep my powerhead and electric systems coated with the gooey CRC Heavy Duty Corrosion Spray and never have any corrosion problems even with my 15" mid dunking my engine every time I come off plane. When I replace any of my wiring, I do try to use the marine copper/tinned conductor marine cable which seems to last forever.
Let us know if you want to meet up with the other 4-5 Allisons here in Jax.