If you wanted to do a leader for lings, 30 or 40 mono or florocarbon would probably get the job done just fine. Lings aren't known for being line shy :) but I understand wanting to fish the lighter line to get your bait to sink out faster. Put a heavy duty swivel on and do a 2.5 foot leader would be my advice. Guys in Nor-Cal do just that casting for stripers on the beach. They want the light line for casting distance but the abrasion resistance close to the bait so the don't get frayed and broken off by the striper's teeth, gill plates, or nearby rocks.