No. You can wear many pheros together if you want but yes, some don’t do so well together - which those are for you is something you will learn with more experience. However, I’d tend to the thinking that less is generally more with pheros and in most cases, using the fewest components to get the job done is mostly best - at least till you get a better understanding of pheros and how they interact to make an effective mix.
TUTH is actually moderated into something more socialy useful very effectively by IO, so you could combine both of those and I have occasionally found it good to increase the none proportion and make Ammo more overt by adding a bit of TUTH, so that is good too - mind you I’m older and can make effective use of more none than a younger guy. This is where you need to do your sweet spot testing to find your effective doses, then start pushing the envelope. eg, you can usually use a more overt mix when going to clubs/parties than you earlier in the evening. So I’d usually have something like TUTH on hand to modify the mix as the night goes-on.
As for IOIs/hits/responses - they can vary widely, from very subtle eye-flirting, hovering around you to very blatent/obvious behaviours like jumping you! Try having a look at this thread for more info on hits: