he's using a dart to push the cls. i believe the dart is rated at 3600gph, but with friction, it'll probably be in the 3000-3200gph (not sure). and with 12 3/4" outlets the flow will be somthing like 250gph/ outlet. he has a few ideas about increasing the flow. altho the toal output will remiain uncheanged, unless he capped off a few outlets, he might pinch some of the pipe closed.
as far as the strainer goes, it was just a plastic housing that screwed into the bulkhead. looked just like one for a powerhead, but bigger. look at a maxijet to get an idea. i think that they came with the bulkheads. saltnoob can correct me if i'm wrong