Good point. You can either do real panning, or the amiga version. real panning would be full left speaker for offscreen to the left, and full right only for offscreen to the right, and somewhere inbetween for on the screen depending on position.
Amiga panning is always all left or all right, with no duplication, and no panning when music is on (it's always on the side that has the free channel)
And yeah. Here are the various channel systems.
DOS with music. 3 channels, with channels freeing up a half second after they are used.
DOS without music. 6 channels instead
Amiga with music. 1 channel as described above
Amiga without music. 2 channels. one left speaker and one right, as described above. MIGHT actually be four, two per speaker, but it's hard to test.
If we want to improve on the originals.
Idealised Amiga. 2 channels with full panning, no check for free channels. Note that amiga only plays oh no once for starting nuked instead of ohnoing for every nuked lemming, and that exploding is a very quick sound effect.
Idealised DOS. 6 channels, with full panning for all. It's the Oh, No! chorus.