Based on my experience, P79 stacks with pretty much everything that you combine it with since its effects serve to enhance/amplify other components rather than project one of its own. You should have no problems using it with Ammo, although if you intend to use the two as a combo (applied separately), I would advise that you apply the P79 first and then the Ammo on top to take advantage of the enhanced sillage/dispersion effects of the Ammo cologne base.
Mixing with other components that do have unique and distinct effects will result in mixes that are blended and in some cases, a combination of the individual effects, and in other cases, a whole new set of effects beyond what was originally expected. That’s why mixing is inherently a trial and error process - you could stumble on effects you never expected, create a super mix that has all the major effects that you were seeking, or make an incoherent soup that seems to have no obvious effects.
There are indeed interactions between components in the sense of steering the mix in one direction or another based on the component’s effects. Try to think of mixing as writing music … Which notes do you want to make more pronounced and obvious, and which ones you want to be subtle? Also, which notes would clash with your other notes and end up ruining the song? Volume and intensity play a part as well.
Kitten has a good step-by-step analysis of the concept in her curious combos post:
I’ve made hundreds of mixes, and I can confirm that you can also stack mixes with each other so that they can produce separate and specific effects based on how much of each mix you apply. The major advantage is that I can fine tune the effects to what I need at the moment, and I don’t have to carry the dozens of components normally needed to produce the desired effects.
Good luck with your exploration of the art of mixing! 