They are flat and different but rare i would think

The look a bit too big to me, might dominate the arch a bit too much? Just my opinion

Pete

Escargo - that's obviously a joke name

To squarey/roundey type shape(y)

Don't Royal Mail use those for the Snail Mail?

From the 2CV nickname " tin snail" which the French shortened to snail "escargot". Drop the "t" and make it into a van for cargo.