Temporarily CHANGE decimal and thousands separator in Word for a specific document

Question

Sometimes I need to write invoices in English, using the dot as decimal and the comma as thousands separator. Unlike Excel, Word itself doesn't offer an option to change this, it solely relies on the appropriate and systemwide Windows setting.

Changing and reverting this setting manually every time I need to write an invoice in English is not really an option. I'm aware that a similar question has already been asked at VBA Word - changing decimal separator but the search/replace solution provided there is not really a solution (and "solves" a different problem). I don't need to do any calculation in the document, the only matter is just the correct alignment at the position of the decimal tab.

I have found that the relevant properties can be read with Application.International(wdDecimalSeparator) and Application.International(wdThousandsSeparator) e.g.:

Sub Show_Limiters()
    MsgBox "Decimal: " & Application.International(wdDecimalSeparator) & vbCrLf & _
    "Thousand: " & Application.International(wdThousandsSeparator)
End Sub

But I have not found any hint yet how to SET/CHANGE these properties.

So is it possible to temporarily change these properties with a VBA macro upon opening an existing or creating a new document (and reset them again to the default value upon closing it)? If so, how? ;) Most likely I'm just too noobish in terms of VBA to figure that out myself. :(

If this is not possible: Is there any way to temporarily change the systemwide Windows setting instead (probably with a combination of VBA and VBScript)?

Any help is most appreciated. And yes, I know that I could use a right tab instead of the decimal tab, but this is just a weak workaround.

Windows 10 Pro, Office Pro Plus 2013 (German)