Alright, LSD is a lot different from mushrooms and has more potential for recreational use. It's more stimulating, electric feeling, and more social (in a bizarre kind of psychedelic way). It is still a serious psychedelic though. We can't tell you for sure if it's going to be a good set and setting for you, because everyone's different.
For me, LSD would be much easier to handle than shrooms on Halloween. The difference in potency between tabs is so huge that we can't tell you how many to take either. I've had tabs where 3 were just threshold, and I've had tabs where 1 equaled a ten-strip of my previous batch.
I wouldn't recommend candy-flipping (MDMA and LSD) your first time, just figure out the effects of LSD first and see how you like it alone. Once you're comfortable with that, then you start some combos.
Unless the tabs are really really weak, I'd just try one and see how you like it. If barely anything happens, then you can just have a good time on Halloween tripping lightly. That's better than being way over your head.
It's up to you, but I hope this helps.