Do yourself a favor and just forget about the damn siren. Our cars are not valuable enough to steal anyway.

.055 or less is what you want to see. My car is a Base/SE model, mine runs .015 to .020. I can leave mine for two months with no 'tender' or charger on it and be just fine.

The common battery drainers are:
Siren
CLP/SSM (usually will have other weird symptoms)
HVAC "blower resistor"
..... anything on battery feed (sorry, but that list is long)

My procedure takes time and effort, but it always shows where the issue is, usually in less than 1/2 hour.