The helium balloon lights either are tungsten HMI, or sometimes a mix. I usually try to get the mixed ones so I can have a halfway color temp between 5500K and 3200K without trying to wrap the balloon with gel.
I don't know the exact wattages -- usually it's a couple of globes inside that can be switched off, and if tungsten, dimmed as well. Usually 1200w HMI globes I think, or 2K tungsten globes, but I don't know the total wattage, maybe 4x 1200w for some of the HMI ones, which would be 4.8K, 4x 2K would be 8K. Just depends on the company and their balloons.
500T would be typical, fast lenses would be smart, how much light you need depends on how far away the light is going to end up, what stop you want to shoot at, etc. Luckily with moonlight, your key can be a little underexposed.