The proper syntax for Opera will likely make the DAS shell command choke.
You can work around this by creating a batch file to wrap the command - I created a batch file called finviz.bat with the following code inside C:\DAS Trader Pro directory:
echo off
set symb=%1
start C:\Users\Kylek\Desktop\Opera\launcher.exe www.finviz.com/quote.ashx?t=%symb%
^^ You'd need to change the program path to match where the launcher.exe is located on your system.
^^ Download a portable version of Opera, so you have flexibility in where you want it, and you can have multiple installed where the customizations won't apply. Can download here: https://www.opera.com/computer/thanks?ni=stable_portable&os=windows
The DAS Hotkey looks like this:
shell finviz.bat %SYMB% ;
You can add the "FocusWindow montagea;" before the shell command if you wish. Not necessary if you make it a hotbutton on the montage.