Just a thought...
If it's literally "deep sea" (Atlantic) fishing you seek (e.g., for sailfish, dorado, etc.), consider chartering out of the docks on the Atlantic side at Islamorada instead.
Islamorada is (IMnsHO) much more of a sportfishing savvy "mecca" and is just a relatively short drive back "up Keys" from Key West.
On the other hand, fishing in the "skinny" water on the Florida Bay side of the Keys with light tackle can be a whole lot of fun too --- and is my own preference.
As always, YMMV and to each their own.