The pitch range for each whistle is from A5 to E7 (which is only 1½ octaves). The text goes red if you go outside this range.
The four whistles are on midi channels 1, 2, 3 and 4.
Channel 5 is the prototype "automatic" polyphonic mode to make realtime playing with a keyboard easier.
The portamento amount is approximate, the final thing may be less responsive.
The articulation is also approximate. Since there is no attack, if you have one note starting exactly after another note ends, they will blur together. I made a CAL script to automatically fix this stuff (on the slide whistle page, and in the github repo)