No they dont work well on paper for attraction purposes unless your wearing the paper on your body LOL.
One, he has never smelled the pheromones on you, I assume so he will not associate the smell to you without your body present.
Two, you have to mail it, I assume and while it may make the mailman who picks up the letter a little hot it will diffuse well before it gets there.
Now if your looking to just give him a certain feeling then you may be able to pull that off with certain pheromones.
Instant Shine would make him feel good. Instant Honesty or Instant Openness may make him more open to reading the letter if by chance he is reluctant to. You would probably have to put the letter in plastic wrap though to stop diffusion sort of like when we get our packages from Androtics and they have been sprayed with Instant Shine.
Cops of course you could not use they would be so smelly
Tisha