Claudio,

I would suggest that each developer run the code for themselves. The difference from the smallest object to the largest "simple" object (that is a non-container) was from ~17K (relation) to ~76K (checkbox) with session coming in at ~71K.

The difference in instantiation times was statistically insignificant (the margin of error being larger than then difference in times)
JimB

>Humm... very interesting, Jim.
>
>so, Session baseclass isn't that "lightweight" class that one said...?