In a group of 3 barbs and 1 monk, it is certainly possible to get 400+ mil XP per hour doing VSORCS, but if took you 30 hours to get to P50, I know already that you won't be able to hit that much in a group unless you're getting carried hard.
For soloing it used to take me about 18-21 minutes, getting about 80-100 mil XP per run. In parties we were getting about 100-120 mil XP per run in about 14-16 minutes.
The VotA segment would take me about 3-3:30 to get 5 stacks, I know Chaz used to be able to do it in as little as 2 mins, and in a party <2 mins was possible (WotB still on cooldown when we entered Desolate Sands). Ideally you want to bait multiple elite packs together to fight at once instead of each individually, this will save you a lot of time in vota. It may be necessary to swap to a mighty weapon between elite packs to help maintain fury, it takes a bit of micromanagement but will typically yield better times.
In Desolate Sands you want to find all the large zombie clumps, this makes a big difference to the XP. You want to cover most of the map, but avoid the large random event spawns because they don't have good density.
In Forgotten Ruins (and VotA too since they share the same tileset), you will often want to run through dead end rooms without rending at first, then rend from the back to the front. You will also want to leave mobs in front of Forgotten ruins in Oasis as well as those near the entrance that you will loop back to. In certain spawns there will be a random room that spawns on the top left that you want to avoid, as it's too much distance to have to backtrack over.
In general you want to know how much time to spend on each type of mob, or in some cases whether to ignore them if they have too much HP to kill efficiently. Ideally mobs should be dying behind you to tornadoes + rend, you really should try to experiment with different paces in each zone to see what yields the best XP/hour there.
For group play, it's important to stay very close together. If you fall too far behind the other players, too many mobs will start dying before you can generate much fury from them, and you'll drop out of wrath or be unable to sprint which will cause you to fall further behind.
Also, make sure to check out Chaz's old guide from when 1.0.8 first came out. The information is still relevant: http://www.youtube.com/watch?v=veYW96MzJTs