[cernst]

I've found the specs posted by the manufacturer to be if you run the equipment at 100% all the time. I very rarely see that.

If you want accurate information and your strips are not metered and your breakers are not metered...I think your best bet would to buy your electrician a case of tastey beverage and ask him to put an amp-clamp on the lines in the breaker box (that's what I generally call a PDU...). For sure, that is the best way to figure out power draw.

I recommend getting one power strip that is metered in a lab setting and running various servers on it to see what the individual load is. Or you could make it part of the installation process to put it on the metered strip to determine expected load before going into production.

Edit:
Think of the cost justification for metered power strips. How much of your time and other's time are you going to chew up to determine this information?