https://imgur.com/a/H0I2wb9
I selected guns Shift-X, radar went to the usual "gun" mode. I then selected sidewinders Shift-S, radar went to a narrow scan mode with 5 bars.
I think I then pressed Undesignate/nose wheel steering button on my HOTAS, and I found the radar was still scanning 5 bars but in a normal-looking wide scan mode. Pressing the DDI button above the number of bars increased this by 2, from 5 to 7, 9, 11, 13, etc.
I was able to increase the number of bars up to 167, where I stopped trying to increase any more.
The scan still progressed as you would expect - starting at the top bar and working its way down, so it was taking a very, very long time for the scan to come down in elevation.
Changing mode from RWS to TWS made no difference.