Shit I just lost the post I wrote and I was about to lose the text for a second time
Anyway my point was that it depends on how much Salvia and JWH's and DPH you have taken in the past, if it is not that much I would take it as a bad sign that you are somewhat sensitive to these effects but on the other hand one drug is not another one, and you embrace this effect. I have had "HPP" as well and still do to a small extent despite not having tripped for a while, and I used to believe that people who make a big deal out of it have the same but they are just complaining about something that doesn't matter that much and is to me like fun or like tripping for free.
I don't think that anymore - people with HPPD most probably have it much worse, so bad that it impairs their functioning whether they like free tripping or not.
We cannot really answer 'what should I take' questions because it is everyones own responsibility to bear and only an educated guess can be made as to the risks of precipitating schizophrenia or HPPD or PTSD symptoms by tripping.
That said if you do decide to take LSD just really pay attention to how much worse your "HPP" gets and how much the visuals die down after the trip has stopped. Take it easy.
Also try to limit your JWH use. Occasional use of JWH's might be okay and I have also started sampling some but taking these more than every once in a while has bad news written all over it because of the high cannabinoid affinities some of these compounds have. I wouldn't be surprised if they have a good potential to cause HPPD like symptoms when used to often.
If you take them more than every once in a while try abstaining for a while and see how that improves things. If it does then it's probably not worth continuing with them because even while you might embrace the effects now they may get worse. And there is no good idea of knowing how much worse or how fast because so much less is known about JWH's then something like LSD.