Being a silver age collector I tend to go for the books that are harder to find, and thanks to roulette44 I've acquired many from him, and even though it looks like showcase 4 has definitely gone up in demand and value thanks to the new TV show and the upcoming DC movies, lets go to the numbers: the lowest amount of CGC unrestored copies has to go to Detective #225 here are the numbers.
Unrestored Copies as per the census
Tec #225 - 150 copies
SC #4 - 241 copies
BB #28 - 642 copies
Hulk #1 - 854 copies
AMF 15 - 1,531 copies