I have the ten pound mold and there can be a learning curve here.
I use pure lead, nothing alloyed or wheel weights. Todays alloys are hard to control, especially wheel weights. I clamp the mold with a heavy c-clamp and place it in the oven at 250 degrees, THEN start the melting pot. The clamp is not placed anywhere over the ball cavity or fin, only on the edge of the mold to keep it closed securely. The melting pot is cast iron and has a pouring lip and a heavy wire bail handle. I can melt 15 pounds at a time in the pot. I use a heavy propane hot plate to melt the lead and when its hot - been melted and heating for 20 minutes beyond melting - I bring the mold down then quickly pour to mold using really heavy weight heat resistant gloves so I can handle the pot's bail handle and the pot. Pouring should be done as smoothly as possible, one complete non-stop pour with the sprue area topped off when the mold has filled. I leave the mold closed for an hour after filling.
Alloys and wheel weight lead are miserable to work with because the metal can cool so quickly and un-evenly, hence the wrinkles in the finish. Some of this trash lead will start to set up as soon as it hits any part of the mold even though its been pre-heated.
The smoke or drop-out will help in smooth filling. The biggest thing is to have that mold blistering hot when you start to pour so the lead will not set as it is poured into the mold. Using really hot pure lead and preheating the mold and clamp will produce balls that are spotless.