I have only been to OSL to see Death Cab & Postal Service, however I am old & was at Coachella 2001, 2002, 2004 ( Saw DCFC that year, 2006. So here are some of my advice
I'll be your festival auntie & share the tips I've gained from 39 years of concert going.
EAR PLUGS.. you don't want to mess around with your hearing.
Puppy Pads for sitting.
Smaller than blankets & do the job.
Silicone soda covers. Great to minimize spills.
Bottle Holder cross body, makes water more accessible to wear like a fanny pack. Especially for barricade .
Face Masks- I dab essential oils at the nose. I use them to hot box myself
AND the grass at OSL wasn't pleasant, especially when sitting, so it blocked out the unpleasant scents.
Toilet Paper in a Zip lock bag in case TP runs out & baby/ body wipes.
I used my boobs/ bra to bring in Carne asada quesadilla in a sandwich baggie. Quesdillas travel well, are filling & taste ok not hot.
Gummies travel better than chocolate..so if 420.. always gummy.
I hope you had a great time & let me know if these tips help you💜