You have the option of adding your own samples to the "Usr" directory (under the "Samples" directory, which is in turn under the "Open Metronome" directory in "C:\Program Files"), which the WAV metronome should automatically make available when you re-run it. Note that all samples must be of the same format (44.1kHz, 16 bit signed PCM mono). "Audacity" is a great, free open source WAV editor that can convert and save audio data into this format.
You can export your settings (e.g., to transfer to another machine) via the "Exp" button at the bottom of the main display. Set "Save as type" to "Registry Files (*.REG)" to do this; double click the .REG file on the target machine to load the new settings. Note that this will *replace* any Open Metronome settings on the target machine. Windows will warn you about the dangers of importing a REG file: you can in this case ignore the warning. Using REG files isn't very elegant, but it does what I need.
You can also export a loop of your current audio output to a WAV file (e.g., to transfer to your mobile phone or something) via the "Exp" button. Set "Save as type" to "WAVE Sound (*.WAV)". You can set the number of loops to save via the "Hotkeys/ Cfg" menu item on the main display.
There are many free applications that will convert the WAV to the more common mp3 format, e.g., "Audacity".
You can assign "Hotkeys" to Start/Stop the metronome at a single keypress (and to control the tempo/ beat type) via the "Hotkeys & Settings" menu. E.g., You could assign "Start/Stop" to "Space", and then whenever you hit the spacebar the start/ stop button would be pressed.
Note that hotkeys are disabled when the cursor is in the "Save Presets" or "Custom" boxes: this is to allow you to type things into these boxes without the metronome clacking about all over the place: click one of the radio-buttons (e.g., "Straight Metronome") to get the cursor out of these boxes.
Hotkeys can be disabled again via the little "X" boxes to the right of each hotkey definition.
You can set the minimum and maximum beats-per-minute via the "Hotkeys/ Cfg" menu option on the main screen. You can also set the increment (e.g., the amount by which the slider varies if you click to the left or right of it or hit page-up or page-down etc.).
Apparently, in Cuban and African music, it is common to place the first few beats of each bar somewhere between where sixteenth and triplet beats would fall. If anyone knows the proper name for this kind of tempo, please let me know (5thWheel@gmail.com).
This can be controlled via new syntax in the "Custom" box. By example:
would play the first 3 beats out of every four 12% faster than the current tempo. The resulting feel is that the first three beats per bar are "rushed", but the fourth lands where you'd expect it to in standard 4/4 time.
You can specify a negative percentage (e.g., "[3/4@-12%]") to make the first beats 12% slower than the current tempo.
You can also specify an absolute tempo, by omitting the "%" sign (e.g., "[3/4@120]" would play the first three beats per bar at 120 bpm regardless of the main tempo).