When using a non-expander backplane with SRCSASBB8I, you'll need to connect a 3-pin SES cable from the RAID card to the backplane, to make the LEDs on the drive carrier work properly.
Also, don't forget the HSBP cable from baseboard to backplane.
Expander backplanes use the combined throughput from from all connections for all installed HDDs. Therefore if you have two SAS connections to the backplane and 6 HDDs, you split the available throughput from the controller among those HDDs. Direct connect is a one to one connection utilizing the maximum throughtput from the controller port to the connected HDD.
Regarding the cabling, there's a cabling guides availble for pedestal systems: