How do you set a new default cell border line width in Calc?

The default line width is currently 0.75 pt, I would like to be able to set it to 1.25 pt. I do a lot of work with tables in spreadsheets and am spending a lot of time resetting the line width every time I wish to make a change.

Almost 2 years and this isn’t answered! even to say it is not possible! My related question - how to have Calc graphs have a visible border by default.