Perfect!
A nice thing is that I don't have to put another Helper inside .\SD2 folder because I run it with shortcut - from same place as regular Dune2, but using different conf (which then [autoexec] to \SD2\SUPER.EXE). Me thinks it works because shortcut "Start in" box shares the path with Helper.
No unexpected behavior to report.
Thank you a lot for your work on this