Hi Paul -
Most people use a full sink line for shad as it can be difficult to get the flies down to the fish with poly leader sink tips or intermediate line.
I've always found catching shad is mostly dependent on getting the fly to the proper depth more than anything else, so I would recommend a full sink/30 ft sink tip if you can get access to one.
You may be able to solve that with a poly leader/intermediate by adding weight but my guess is that it will be challenging to get flies deep enough. I'll let other folks chime in as well though.
Good luck!
Brian