im using a second hand extreme HD 5 puck in mine, seemed to work just fine
L series slave will work fine on the CA box, used the same hydro clutch setup for my L series and CA

CA is the same size clutch plate an L series 6 cylinder, 225mm
pressure plates have different bolt patterns, you could redrill an L series flywheel to CA pressure plate pattern if you really wanted to. then you could get really good clutches...that are also really expensive

an excedy HD clutch for an L series is about $180, for a CA its like $500-700