Then the load isn't very high. If your lazy jacks do double duty as a topping lift then the loads could be a few hundred pounds, and you'll want to pick up the load using the main halyard clipped to the boom end when you anchor or leave the boat on a mooring, and subject to wave action.

Topping lifts and full roach mains don't go well together. If adding full battens it's common to add sail area with more roach.