pre/post floats are the norm for every coastguard operation i've seen,
and having been involved in it its also something i do on my own boat.
I dont actually have a checklist with numbers on it, but i've got a
steady routine i go through with my boat. Checking the bungs, fuel
levels, rigging and sails is about it. Im the only person to use the
boat so i dont frequently go through all the items in storage, but i do
remove them all and check them about once every other month. More to
be able to remember what there is than anything else i guess.

As far as the batteries go... you can easily add an extra battery to
your existing one but put an isolator on it. This acts like a one way
switch, the battery can be charged by the charging system
automatically, but if the voltage in the system drops the battery will
be disconnected.