LAH Thanks for the video !
Been casting boolits since `83 & have a few hammer handles that look just like yours !!!
While it looks like your beating the mold apart the hammer handle isn't heavy enuff to damage but enuff to give a good jarring .
With the gang molds just make sure it`s open good before "tapping" it is the trick to not damaging mating parts.
I have a few lee 6banger molds ,but mostly use NOEs 5 holers now, they drop boolits like rain!!
I used to cast standing & setup was close to yours, but back, knees,& feet make me sit thru a casting session.
Sitting in front of a 20 # pot of 750f lead WILL make you pay close attention to what your doing & in what order!!!!
PS: I like a 24oz Ball Peen handle ,straight grained hickory.
Happy Casting !!!
GP100man