Connect the 2nd CRT to HDMI via VGA using an adapter, then use VGA to SCART. Make sure you are using DirectVideo=1, in the ini.
This way, you can keep both CRTs connected at all times, and have the second CRT rotated on it's side.
This is how I have mine set up. I have my main CRT, a 19" JVC TM-H1950CG connected via SCART - VGA-out to SCART cable made for Mister. And a Sony PVM 14M4E, rotated on it's side, and connected via HDMI from Mister, using a BENFEI HDMI to VGA Adapter, then a VGA to BNC cable to my Sony PVM.
This works great, but does take up a fair amount of desk room, especially the JVC Monitor.