Since rings count as weapons, dont waste an Um rune trying to make it add resist, it will add Open wounds, i found that out the hard way, the only way i know of to get resist on rings from a socket, is a + to resist jewel, as for amulets, since they count as shields, an Um rune would add great Resistance, where as a Zod rune would add resistance, a little less then um, but it also adds to max resist (so it can pass 75).
Hope this was helpful =)