Hi Hob, welcome to Pherotalk 
To my knowledge, there shouldn’t be any adverse reactions from wearing both pheromone products and regular colognes. I would not spray one immediately after the other, but other than that, there’s no trick to it. Check out this thread for more info on application and application points.
As to the products you mentioned, those are good choices! Let me offer some advice concerning when to wear each product. Ammo is a great all around product. I use it in place of an everyday men’s cologne, although you can wear both at once as well. It provides a slight sexual edge, combined with a dose of social pheromones and some mood enhancers. Besides overly somber occasions, I could see myself wearing it almost everywhere.
TUTH is aimed more at overt sexual attention. If you think of pheromones as non-verbal communication tools, TUTH is a billboard with “I AM A SEXUAL BEING!!!” written across it. You probably wouldn’t want to scream that out in your place of business, or in your everyday life. However, in the right social situations, or in an intimate moment with a lover, it can greatly intensify the experience.
Hope I’ve helped