Is ammo (summer) effective alone? ive read that it gos well with others such as Instant shine etc but is a spray or two effective alone
Yes, perfectly effective - Indeed the Summer Ammo formula already contains TAA, which is the main component of IS, so if you are adding IS, you usually need less of it, if at all. Personally I’ve not found it a huge improvement and IG/P75 suited me far better.
The other reason a lot of us add stuff is that we are older and need a different proportion of certain components to suit our advancing years better. Summer Ammo is very well balanced for someone your age though and should blend nicely with your own phero signature. 
nice one mobo. can i still use my own aftershave? does it matter when it comes to layering? aftershave, afew minutes break, then apply phero or vise verca? or is it simply apply them to different spots (wrist, neck, chest)
Also, do girls pick up a phero scent more so than an aftershave fragrance?
Layering is just fine - Spray one, let it dry then spray the next phero or cologne.
You can do different points as well in order to avoid overloading app spots. I tend to work with socials in from the periphery (wrists, forearms etc) whilst sexuals/status work from the centre (neck/throat/upper chest) outwards. Don’t get too hung-up on application points though, so long as its open to the air and with good circulation, its an app point.
Oils are the only thing you need to keep apart from sprays - never have these sharing an app point or you will wreck diffusion.
Its not the scent they pick-up on, all the scent does here is carry the pheros into the air around you and the pheros are absorbed in other ways.
Thanks for the post. I appreciate it as we’ll due to bring 25 and knowing if should be adding IS with Ammo Summer. I have been testing it since I got it a couple of days ago. I plan on working it with one spray to the throat for good diffusion when I go out to social event or college. I will keep you posted.