Comparing Shrooms to LSD is like comparing ketchup to a tomato, although they are hallucinogens they are very different and it really all depends on personal preference. Personally i enjoy LSD much more then shrooms, in fact id bet i probably wont eat another mushroom in my life... Overall for me Mushroom's are to much for me to handle, the body high is outrageos and it generally sends my mind into panic mode. With LSD i feel like i have much more control over myself and my thoughts which in turn allows me to gain more from the experience.
Most bad shit you've heard about LSD is lies, Lsd is one of the safest drug's you can consume... Yes it might change your perception on life... But then again, isnt that what your looking for?
As far as tripping with 8 other people id really recommend against that considering it's your first time. Keep it to you and a couple friends you REALLY trust, friends that you could break down in front of and not feel bad, trust is key with psychedelics...
As far as how many micrograms can fit on a blotter, im not sure. I think the average shitty blotter has 40-80 micrograms per hit so you would probably be hard pressed to find blotter holding the maximum amount of LSD... If you do grab as much as you possibly can haha.