By Perko, I presume you mean battery switch. I shut off all the
batteries on my boats when I'm not using them. You might want to wire up
a bilge pump/electric float directly to the battery if it isn't already,
so that any water that gets below the deck can be pumped out. But that
isn't much of a worry on a SeaPro at a dock.

I would definitely tip the engine out of the water, too, when the boat
is docked overnight. If you are in a theft area, buy a prop lock nut.

Are you in fresh or salt water? That determines what sort of sacrificial
electrode you need.

You are correct on the battery switch. I also neglected to mention the
bilge pump (auto and manual) is already installed. Tilting the engine
is really not a problem and so far theft has not been a problem - I
usually leave fishing tackle in the boat when docked but I'm sure I'll
regret that someday.The water would best be described as brackish I
guess - we're at the end of the bay off of the Intracoastal Waterway
and within a few hundred yards of a cut to the Gulf but also fed by a
freshwater creek.