What vacuum pressure is required for casting?

[FreshFund]

I know you need at least 28hg+ for degassing the investment, but when pouring the gold/silver into the vacuum caster - what pressure does the chamber need to reach? Is it also 28hg+ or just a slight assistance like sipping a straw?

[josef1]

I think the more you can get and the quicker you can attain max vacuum the better, it results in a denser casting.Its difficult to get a really low reading because your pulling a vacuum through a pourus flask not from an enclosed space