On my deck-over, i have the 195/50R13 spare under the deck, inbetween the Vee of the towbar, secured with 3 wheel studs.
Its so low that i'll have to crawl under it on my back, pull the spare on my chest, then push it up with my elbow on the ground and the other hand putting on a nut.
Since i only take it off during calamities underway, the penalty of getting my back wet on the street is acceptable because the advantage of never forgetting it, outweighs practical drawbacks.
In the 5 or 6 years i rebuilt it, only my pal had to use the spare tire because he found a screw.