NoiceGuy Nolan (youtube) posted a recent vid and asked for tips for playing with a 5 man. I posted some of our tips as a comment, and figured some other people might have fun with it if I posted it here.
Pick a shotcaller who decides where you go on the map macro wise. They don't micro manage – they just pick the next location.
Try not to hold spots. When you stop, you lose orientation – when you reach a location, clear it and move on – you'll maintain momentum and clean up your callouts.
Everyone hates it but get used to using cardinal directions. North entrance big red, west dorm field, west new gas, etc. It's a pain in the ass to learn but it makes people learn map orientation and really "think" about the orientation of the squad. It becomes natural eventually (I promise)
When clearing a building, max 2 guys clear the building and the rest lock down the perimeter outside. You want to ensure no one comes in/out of the building so your guys can do their job inside.
When clearing any location (esp outdoors), pick left/right wing. If you're left wing, you're moving clockwise around the location from the point of entry (right wing moves counter clockwise). This keeps your back against the wall and if you draw fire, your buddy is already in a pinch formation for a guaranteed win.
Keep comms to an absolute minimum. The only info you need to relay is where you're moving, and if you see a contact. If you confirm scav or pmc, then upgrade the contact call to a scav/pmc.
Finally (and most importantly): Don't make a micro shotcaller necessary. Know what you're supposed to do without needing to be managed. If your point is watching forward, automatically look elsewhere. Move point to point, and know what to do when you take a site. If your buddy called left wing, you call right wing. Someone else call point, and let your shotcall sit back to judge for a retreat. If you're clearing dorms, two people lead the building clear and the rest of you post up in bushes outside to airlock the building. Don't be the guy that clogs comms up and needs to be told what to do!
Sidenote – I'm really interested to hear other tips if anyone has any. It's super fun to hear how others manage their large group sessions on tarkov (being that it's notoriously punishing to run groups larger than like, 3 people).