I thought it maybe easier to install ETKA, ELSA and Bentley on a PC running windows XP so you don't have the bother of virtual machines, driver issues etc.. You can buy used Dell PC's with XP for next to nothing.
Once all the apps are running you can put the PC somewhere out of the way, no need for a screen or keyboard but it is connected to your home network by wire not Wi-Fi. Then when you wanted to use ETKA, ELSA, Bentley just boot up the PC using Wake-on-lan, wait a minute, connect to the PC using a VNC viewer and the XP desktop will be a window on your Mac. From this window you can use ETKA, ELSA, Bentley....
VNC is a method of controlling remote computers. The PC would need something like RealVNC Server and your Macs RealVNC viewer. There's also a viewer app for the iPhone. All free I believe.
