I've done acid a few times, I thought I'd give you my input. Personally, I have always enjoyed taking acid most when I'm alone, I just feel like I get the most out of it that way instead of constantly being distracted by my friends. That being said I have also had great trips while with friends, just make sure those are people you really consider to be true friends that you are comfortable with. I'd recommend you guys to have a "safe place", like an apartment, where you don't have to worry about anyone coming. Just lock the door, turn off all your phones and put on some chill music on the tv along with something nice to watch. I would make sure the apartment is clean as a messy atmosphere can be overwhelming. Other than that just have a couple of benzos around if you can get your hands on some of those, even though they may not be needed it can feel good to have them nearby just in case someone has a bad trip and does not want to trip anymore or if it's affecting the rest of you in a bad way. I'm sure you will all have a great trip and props to you for making sure you and your friends are prepared.
Edit: Forgot to mention that you should make sure that you go into the trip with a good mindset. If you guys are not feeling it, wait until next week, when using psychedelics you should make sure you really wanna take it right now, else you'll be stuck there tripping for 12 hours wanting it to end. I think the best way to have a good acid trip is to be well prepared, be aware of the risks and be in a good mindset going into the trip.
As for the weed part, I wouldn't recommend it to people that haven't used acid before. But since you have used LSD before, see how you are feeling while you are tripping, if it's too intense, skip it, or wait until the peak is over. Also it's better to start with a little and smoking more later than smoking too much and being overwhelmed.
Edit 2: Benzos are a prescription/street thing only and the only reason you would take them is if you are feeling too overwhelmed and you don't want to trip anymore. You don't take a tab of acid along with a benzo to make make it more manageable, it's just a tool if you want to end the trip early. I've never had to use them or had them with me, however, I have read about it. I recommend you to, as always when consuming drugs, read up on it before if you decide to take them with you. It's always best to be educated about the stuff you put in your body, whether it's drugs or food.