"Which cannabis products do you recommend for PTSD?"
All cannabis can affect the dopamine, serotonin and norepinephrine receptors just as MDMA/Ecstasy can. Therefore you can get negative side effects such as hallucinations, especially with edibles, dabs or bong hits, but also positive side effects such as a sense of general happiness, increased sociability, relaxation and reduced anxiety. Any of these side effects can also show up in reverse and make people have less sociability, depression and increased anxiety for instance, especially with abuse.
For PTSD, I would recommend an indica hybrid as the hybrid will take away the anxiety and paranoia that cannabis can have as a side effect, especially with Sativa products. An indica hybrid will help erase dreams at night hopefully helping with nightmares you may be having. Best of luck!
drb