Hi. This is just my 2 cents worth - I had a fearful, agressive, rescue dog who passed away a few year ago.
My dog really started to calm down when I committed to making his life as "other dog free" as possible. I had started reading a lot of sound advice on Victoria Stillwell's website/forum - highly recommend that if it's still in existence). Walking routes where it was unlikely to meet other dogs (lots of trial and error!), telling people firmly and directly that other dogs were not allowed to come on our propery or to "say hi" when we were out and about.
It's hard not to focus on other people's perceptions of how dogs "should" be. But if you keep going with the trial, I'd strongly advise telling people directly "do not bring your dog over".
Every situation is different - we got to the point with our dog (after a year plus of strict dog avoidance) where he was relaxed being in the vicinity of other dogs (but not if they approached him).
Again, just my 2 cents. There is so much stress on all sides (human and dog!) adjusting to a rescue situation, that cutting out as must stress as possible was the way forward for us. Good luck and best wishes, whatever you decide!