Advice on taking LSD for the first time.

My friends and I are decently experienced with psilocybin mushrooms and are eager to now “become the pilot” and take some acid. We plan on dropping at the prime music festival of the year in South Africa (where I am from) which is coming up in a couple of months. I am very excited but the butterflies in my stomach that arise at the thought of taking LSD are my motivation behind this post.

My concerns are as follows:

1. How can I assure that what I will be taking is pure LSD?
2. What is the best, tried and tested method of making sure that I am taking the correct dose? (By the way, I don’t even know what that dose is)
3. Is a music festival the best set and setting for this first time experience? (Keep in mind that there will be plenty of people that I know that will be there)
4. Any music festival LSD tips and tricks?

Any advice is welcome and I apologize if this isn’t the right place to be asking these questions - I am fairly new to Reddit (loving it by the way).