Plenty of info on app points here:
The only thing you need to remember is that if you have the oil version of A314, you must keep that apart from any spray pheros. Spraying alcohol over oil (or vice versa) will wreck the diffusion.
However, if you have the spray version of A314, layering it with other spray pheros is fine. Just leave a minute or two between each layer to dry down.
A314 does indeed go well with Ammo. There are many threads about this. My take is that smaller doses of A314 are in order here.
Yes, all environment factors affect diffusion. Wind, heat and humidity most. Also enclosure - being out of doors will make bring your diffusion range right down and the wind will disperse your phero cloud/trail very fast. Look for shelter/cover when using pheros outdoor and keep your targets downwind but best still, look to getting them indoors - where diffusion and phero range is optimum.
Saying that, you should still find you get a good four hours or so out of each spray application and more like six from oil - unless it is exceptionally hot and muggy.