What has worked for me in casting a little over 20,000 of them...
As shared, candle soot the base pin as well as the mold cavity.
Using a piece of wood or broom handle section, when the lead has solidifed (NUG 2-5 seconds or so depending upon lead and mold temps)... give the mold a whack across the top of the sprue cutter.
This will NUG set up a "vibration" through their mold below and free up the base pin. Then pullout/extract the base pin, turn the mold over and allow the Miie to fall. I use a folded up old towel to keep splashing water away from molten lead and the risk of splatter or explosion. (Some lads argue that water quenching "hardens" lead, but that is another discussion.)
Aluminum type molds like Lee work fine, but better if sooted. In my experience, I went to steel mold blocks with base pins as I was wearing out an aluminum mold at the rate of one a year to where it was not aligning perfectly causing seems, or the "floating" base pin got out of synch and/or alignment and prevented the mold from closing.
Others' mileage will vary...
In gleichem Schritt und Tritt, Curt Schmidt
Not a real Civil War reenactor, I only portray one on boards and fora.
I do not portray a Civil War soldier, I merely interpret one.