Showing the relative lengths of the clamps for each wheel: (Rimmers)

V8 wheel stores upside-down, using a short clamp, with up-turned 'ears' and not down-turned as drawn in item 9 above:

Making a handy extra storage space:

The Rostyle clamp length means that the wheel has to be stored outer face upwards, but it can also fit upside down without fouling the threaded boss in the boot floor:

The V8 clamp is a perfect fit for that as well:

Wire-wheel clamp fabricated from an old Ron Hopkinson rear ARB drop-link, a 3/8" UNF threaded section welded to one end of that, and a clamp-plate with 'wings' and plastic protector fitted to the other end:

Smooth top surface avoids damage to the cover carpet: