RIG
A simple running leger is the most effective rig, but for common skate, short hooklengths of just 12-15in of 250lb mono are recommend for two reasons.
Firstly, short hooklengths are far less likely to tangle when dropping down to the bottom in very deep water, and secondly, short hooklengths are far less likely to result in deeply-hooked fish.
Above the hooklength, your rig should incorporate a 10-12ft rubbing trace, again 250lb mono, to prevent the line from getting cut by the fish’s tail. Use strong, high-quality swivels of around 300lb BS.
The hook should be bronzed and barbless to facilitate easy unhooking, and to ensure that, if necessary, cutting the trace and leaving a hook inside the fish’s mouth will eventually corrode free. A size 12/0 bronze O’Shaughnessy hook is perfect.