Mutt,
My quote - "A good service provider will supply OEI data to comply with the SID (usually much more restrictive)"
Your quote - "Not always true, we have particular airports where we know the required takeoff weight, its not achievable on any of the SID tracks."
To qualify this, SECONDARY data is made available for those SIDs which can accomodate 'reasonable' weights. Certainly not all of them. PRIMARY data is always available via the OEI route, invariably different to the SID.
Regards,
Smokey