A staple of of early D&D is the "1 in 6" or "2 in 6" chance for surprise, finding secret doors, and so on. Recently, some of the retro-clones, mostly noticeably Lamentations of the Flame Princess Weird Fantasy Roleplaying use this as a semi-skill system. My biggest problem has been that 1 in 6 is too granular. I was considering doubling all the chances and making them on a d12 and doubling specialist skill points. I guess you could even triple them and use a d20 (with slightly lowered chances of success).
Has anyone experimented with this? Is it worth formalizing or just having them roll a d12 when I need the half-way points?