Sarah,
Because new diabetics have no history of doses/reactions, we tell them not to shoot under 200, but to wait 20 minutes without eating (which can raise the number so it isn't "true") and retest to make sure the number is rising and over 200. Going forward this would be the best approach until you know how he reacts to lower numbers.
You were going to get strips today, right? Please post here on Health before each shot for advice until you get the hang of this sugar dance. O'Malley is giving you some nice low numbers and we want him to be safe and not go dangerously low. The Levemir forum is just not very busy so posting here is probably wisest for awhile.
For reference, a regulated cat ranges from the 200s at preshot to below 100s at midcycle, but not under 40 - which is approaching a number too low. A cat in remission, off insulin, ranges from 40-120.