GST component on a line

Good morning,

Just wondering if there is a setting I may be able to tweak to be able to enter the numerical value of the GST component on a specific line, as opposed to selecting a tax rate that applies?

Also, is there a way of viewing the accumulative total of the GST on a purchase invoice without having to select update>view? (That is, is there way of viewing the running total, prior to finalising the purchase invoice?)

Thank you.

In short, no and no. Sorry