I have no personal experience with Pmag or any steroid. But a general rule of thumb would be to take the substance in equal periods of time at its half life. So if the half life of Pmag is say 8 hours, try to take an even dose every 8 hours. But not within 4 hours of bed, it can mess with sleep patterns I believe.
So perhaps 2 in the morning, and then one 8 hours later?
i'm sure somebody with experience will back me up on this.