Amount of cells in a range

For starters, I'm stuck with merged cells, can't change it

I need to come up with ways to work around this.
Say I have a merged area of A1:A*, what I would like to know is how many columns are actually used in this merged area.
A1:A4 would return 4, A1:A8 would return 8, A1:C8 would return 8 et cetera.

Now I've played a bit with MergeArea.Address and although it returns me the correct range, I'm stuck with actually using it further.

Any ideas?