Welcome to Bluelight
We don't allow SWIM-type stuff, it is annoying to read and doesn't fool anyone - for a slightly longer explanation check the forum rules / guidelines.
Also source discussion is against the rules so we don't really talk about where to get drugs except the very general. Legal discussion is not really done either, if you order something illegally you might get away with it, or in the case of an interception get just a warning, or - I guess this is in extreme cases - a potential charge of posession. I do not live in the States and personally doubt that it would come that far, but it is a risk that is just up to you to take or not. We are here to help with information about the actual drugs themselves.
So that is regarding legal safety, if you are talking about trustworthiness of vendors... well some are fine and some maybe are not, it's impossible to say if we cannot discuss details.
A question you pose that we can actually get into: what strength?
It depends on whether you can weigh your doses using an accurate scale reading 0.01 grams or 0.001 grams. Higher than 5x is really only for those with plenty of experience (though reverse tolerance is also an issue) or an accurate scale since the stronger the extract the smaller the dose. Most people apparently just eyeball it and are then surprised about unpredictible effects. Just because it is a herb doesn't mean you can treat it like weed.
Good luck and safe journeying
Check our central threads, we have one on scales, Salvia Divinorum and plenty of other topics. You can use the links below in my signature.
Please follow our rules or we're gonna be forced to close the thread.

Always make a descriptive thread title so that everyone can see what it is about, I edited it for you. Thanks!