CYVR SID Question

[lostaviator]

Curiosity has me... Question for the YVR guys. What is the difference in the SID's and parameters for assigning a certain SID? Most airports are self explanatory, like YYC using one set when in parallel ops that include a turn to provide the separation and another set for only runway. But in YVR is seems you can have 3 aircraft lined up in sequence each on a different SID. And even flying the same route, taking off the same runway some days we get a SID with a turn, and other days its straight out.

[PointyEngine]

EDITED: Not applicable to original posted question..

[16SidedOffice]

The Richmond and Stanley SID's are for prop only as indicated on the plate and are given to southbound (either destination or initial direction towards their on course). The YVR SID is straight out and generally issued to aircraft filed northbound (in a nut shell between V317 to the west and V338 to the east). The Georgia and Fraser SID's were created for south and eastbound jets to use visual departure standards between them and the a/c on the straight out YVR sid, these SID's are only used during the summer when traffic demands a higher departure rate. The reason for having different named sids for each end is to avoid having a/c mix up the initial headings which has happened on more than a few occasions.
Flying the same route on the same day and departing off the same runway ay YVR, the only way you'd get different SID's is by swapping between a prop and a jet. On a side note, the parallels at YYC are approx 7100 feet apart vs 5600 at YVR and 11850 between 24L and 23 at YYZ. Arrival flow rate wise, they are generally the same between YYC and YVR assuming the weather isn't causing issues.