Piece of lead on bottom to make a pool when it melts. Pot filled to the top, lid on. For WW's that will drop down as they melt I overfill the pot so when I see the lid drop to the pot I go add more WW's to the top. There is still a layer of not melted WW's on the top of the melt so my new weights don't go into the melt but have a chance to heat and dry.
Doing that adding as the pot melts I can fill a dutch oven. Don't know if it is faster or slower than all at once. Do know the thin slab of lead from last melt in the bottom of the pot speeds things up. Once it melts it transfers heat to the WW's on the bottom much better. I would say pot lid drops for the first time at least 15 minutes sooner with that lead on the bottom.