Ohmmeters have their own power source, and should never be connected to any circuit with voltage on it. Connecting one across a battery would either smoke the meter, if it's an old analog type, or make a digital meter read an overload. Are you sure that's what you're using? If so, your readings are meaningless. Your gauges should not be powered up unless the ignition switch is in the run position, so they're obviously wired incorrectly.
Try disconnecting a battery cable, and use a digital multimeter with a 0-10 amp setting on the dial. Connect one meter lead to the battery post, and the other lead to the cable you just removed. The meter should show less than 1 amp of current draw, the smaller the better. Only things like a sound sysytem or maybe a clock with a "keep alive" memory need an unswitched battery voltage connection, and that circuit usually draws only a fraction of one amp. If the parasitic current drain is one amp or more, start disconnecting circuits one at a time until you find the source of the drain, and fix it.
Jerry
