Baseboard diffuser instalation problem

[Uwe K.]

This is a problem I don't even know what to type in Google for to not just get baseboard offers offered for sale.
I am helping a friend to fox some odds and ends in an office he is renovating, incl. putting new baseboard diffusers, the standard kind that sits in the corner between wall and floor.
Obviously these things are designed for a 90° angle, but how do you work around it if that angle is significantly more than 90°? You either have a gap on the wall or on the floor. I haven't seen how big the gap is yet, he just told me it is quite obvious and visible.
Anybody got an idea for a nice looking workaround? There are potentially 23 of those problems, but hopefully only one wall with 4-5 of them.