Most magazines state that one inch in the fork length is worth 1 degree on the head angle. I've never measured it so can't verify that. But working on this idea, you're talking less than a degree.
Look at it like this – 2cm is the difference, or to put that into context, the width of my thumb is the difference. Do YOU think it will dramatically change things? No, me neither. If you like the things just get one, try it, and if you don't like it with the Reba's (which are not that much shorter than 140mm fox floats), you could sell them and buy something longer.