on level of fuel for storage, it all depends on your pattern. If you store in a climate where it's somewhat humid, you really are better off to keep it as full as possible, as when the temp and baro changes, the fuels will expand/contract, and the tanks will breath outside air in/out. The air WILL condensate inside the tank, making water that will remain in the tank. So, the less air space there is to breath, the less condensation there is - this is a proven fact.
Now, if you store and the tank is empty, and you don't do anything to remove the moisture before you fill you're more likely to have water in the tank.

Also, if when you store, if you just add stabil to the tank, but don't mix & run the fuel into the engine, that's almost as bad, as one of the other killers of engines is the varnish and gum that will develop in the engine fuel lines like the fuel rail and injectors, and that will lead to a sticking injector. If it sticks open, that's not too bad as it will just run pig rich and be dogy running, but if it clogs and doesn't squirt enough fuel, that jug will run lean, and that's what kills motors fastest

just food for thought, but almost all reliable wrenches will recommend full tank of treated fuel for storage, w/ the treated fuel being run into the engine as well.

this is much more important on carby engines, luckily the sealed systems on HPDI-FI seems to be less prone to fuel degradation since it's air contamination that causes fuel to go bad faster, but older throttle FI will leave fuel vapor in the crank and on the reeds that will go bad and cause stuck reeds due to varnish.