TvZ Banshee vs. Spore Crawler

1 banshee vs. 1 spore crawler - spore wins w/ 250 hp left
2 banshee vs. 1 spore crawler - banshee wins w/ 1 banshee 20 hp left
3 banshees vs. 1 spore + 1 queen - 1 banshee left - HP/outcome depends on micro

If queen has mana for at least 1 transfuse - target queen first otherwise target spore first

I don't necessarily see how the first two statistics are relevant seeing that you will almost never encounter a lone spore crawler without a queen nearby. Also, banshees hit a critical mass at 5+ banshees and are excellent expansion killers.

At 24 damage per volley it take 17 hits to kill off a 400hp spore crawler-
5 banshees = 4 volleys/ 5 seconds
6 banshees = 3 volleys/ 4 seconds

Versus hatcheries at 1500hp it takes a total of 63 hits -
5 banshees = 13 volleys/ 17 seconds
6 banshees = 11 volleys/ 14 seconds
7 banshees = 9 volleys/ 12 seconds

Cloak is also very useful if they don't have an overlord near an expansion.
Focus down perimeter detection spore crawlers (usually only one) and then take out the hatch.

OS morph time is 17 seconds, which is exactly enough time for you to finish off a hatch and retreat with a minimum of 5 banshees.

A banshee's move speed is 2.75, which means it can outrun Zerg detection during a retreat, unless they have upgraded OL/OS speed, which lets overseers keep up with fleeing banshees allowing mutas to take them out.

Lastly, the minerals/gas it takes to get 5+ banshees and cloak is very high, and by no means should this process be rushed. Start out with harassment and gradually build up.

I'm all for using a couple of banshees for early game harass but I cannot stress enough how important it is to not lose them. Putting 450/300 into 3 more banshees after an initial 2 makes your banshees incredibly more effective at denying Zerg expansions. You may not have air superiority, but you will have a good amount of map control.

We should determine the breakpoint where a banshee's "most convenient hiding spot" is far enough away from your nearest base that it's a better idea to drop a MULE to repair it than to send an SCV. (Obviously, the place you want to bring the banshee back to depends on how fast you want to be able to use it to attack again--if you just plan on using it in a push later on, maybe it can come back to the base and you definitely don't want to burn a MULE on it--if you want it to be ready to return to the fight by the time your next banshee finishes at your proxied starport, it should be a lot closer to your opponent.)

I think that you should never be in a situation where you should burn a mule. That's just way too many minerals to waste for a job that could have just as easily been accomplished by sending an SCV to the opponents 3rd, or other areas depending on game time. Also, the SCV doesn't die after 90 seconds, and can keep repairing as needed, while scouting for enemy expansions.

For example, in TvZ, I open with 4 fast hellions and send an SCV to the 3rd so I can repair on the go. Later, I send in 2 banshees to pick off a few drones and retreat back the the 3rd for more repairs. Lastly, I can see when the Zerg decides to take his 3rd.

Well, depends on how much you need the simultaneous scouting information, really. Though I suppose I don't think even on the largest maps, where the only good hiding spot is right near his base, does it take 270/46 minutes to make a round trip. If ever there is one, though...