Flexi shaft attachments

Hi Everyone,

My name is Paul,

Hoping you can help answer a few of my questions ;

What are the best flexi shaft attachments for grinding sprues &
smoothing them once their cut ?

What is your wax of choice for making a wax model/pattern for
casting, I’ve been using foundry wax and notice the surface is not
inconsistent i.e bubbles, holes ?

Is a vulcanizer superior to making a mold out of polurethane i.e
polytek 74-30 ?