MIDI Options page sets MIDI parameters for the newly created or recognized MIDI files.
GM Patch (instrument) - current version of WIDI can not determine which instruments are played in the piece, but it can assign resulting notes to any instrument.
Key - you can assign any music key to the resulting MIDI sequence. It does not transpose the piece.
Determine automatically controls whether tonality detection will be performed. When setting this checkbox, tonality that is set manually is ignored.
Meter - you can use this parameter to set the meter (2/4, 3/4, 3/8 and so on) of the MIDI file.
Tempo sets the tempo for the MIDI file.
Note: tonality detection and the usage of tonality information is described in How WIDI works section.