You can try setting it on registry so your custom profile folder will be used even if Opera isn't started with the customised short-cut.
In this case, I think you'd have to edit the commands in these keys:
Maybe the HKEY_LOCAL_MACHINE ones too/instead or:
Your changes will be overwritten though the default browser for those is ever modified.
You might be able to edit:
for example instead, so that when Opera is set as the default browser again, all the commands in the other keys are updated too. For stable Opera, that might be:
There are others besides Opera.Protocol like Opera.HTML for .html files. Always look at the command though first. Some of the keys might be for old Opera 12.
Basically command-line options don't help much except for shortcuts unless you change them in the registry too. If you can specify the user data path in a file that opera.exe can read (maybe look at chrome configuration docs), that'd be better.
i enabled "Touch events" and "Touch adjustment" - but the scroll bar and also the X to close the tabs wouldn´t be bigger or wider. The "menu" with back/forward icon is getting bigger - so i think i am in "tablet" mode with opera.
How i said - opera is for me the best browser for Win 10 and touch-mode with fingers - but these two improvements would be very great - perhabs in a future release. Perhabs you could make it that everyone could configure the size of the UI in options? I know, this is not easy to implement - perhabs "experimantal" in "opera://flags"?
Thank you very much