for all models of the OM2SP, OM4 and OM4T/i when not being used turn the shutter speed dial to B this disconnects the battery circuit and prevents battery drain
From what I have heard, this method doesn't work. Perhaps John Hermanson can tell if it holds true or not?

At any rate, battery problem on the 4T(i) is a non-issue, because they all have a different circuit to the plain 4 of old. My OM-3 does use its batteries a bit quicker than my 4Ti, but not to the extent that it bothers me. Plus on the 3, the batteries only drive the metering anyhow. And who needs metering at all times anyhow?