Use Waxoyl on the inside of the frame. WD40 is not so good and just runs out. Waxoyl is brilliant and sticks well to, you'll only need to use it once. Halfords to it in aerosols or huge tins of the stuff.
I used supertrol on my Marin build - It's kind of like a thin waxoil
Seems to have very good 'wetting' properties - I didnt need to treat the headtube - it crept over the dry surface completly - just from the vents to the top & down tubes
Rocol Moisture Guard works, dries greenish an tacky,
use white spirit to clean it off.
Ok for long term storage, too much like hard work cleaning it
off for regular use.
There are lots of bike hangers that fix to a wall,including one that supports the bike by a pedal
Lying flat against a wall shouldnt take up too much room
Or throw out -wife or 1-2 kids
The loft would be a good place to store them,as its likely to be warm and damp free