Wotlk MM hunter question

How does MM hunter calculate its rotation and i’ve read at a certain armor pen it drops arcane shot. Does it know when to drop that is it calculated in or is it still arcane shotting even at higher arps? and does hunter in general involve trapping on bosses? because im not good at doing that so I don’t when im MM and just use black arrow when I go SV.

Arcane Shot really isn’t that great a spell in wotlk - it doesn’t take much armor pen for it to be not worth casting. For simplicity we assume MM is not using arcane shot.

We assume players are using explosive trap instead of Black Arrow, since it is better. This does not significantly change what gear would be picked, though, so you don’t need to worry about it much from a gear optimization standpoint.