For what it's worth, I have a Lee production pot (the 10 pounder), one trick I found to slow down the spout freeze is to let it drip while casting. The Hot lead constantly dripping seems to help with this.
I found the extensions to raise the pot up 4 inches at a local shop some years back. Without them, this trick was impossible. The pot and the base are to close together.
I put an ingot mold under the spout, and cast over top of that, all the while, I don't drop the pour handle down to hard and let it drip the whole time.
I just keep moving the ingot mold, and when it gets piled up to high, I dump that lead into the sprue can.
Maybe not the best approach, but it has helped in the past.