Have Fun! I didn't hang for Particle, but heard that he came out and jammed with them also...I was slightly bummed, but was told that Particle is "like" Phish (Particle fans call them a jam band--kinda along the same vein as the Grateful Dead--and I don't get them
) Aside from the fact that I was starving...the show had a 9PM start time and I was hanging on South Street at about 3:30PM--wasn't sure if there would be a line from GNR fans or what to expect really...luckily (no harm\derogartory remark intended) none of those folks showed up...so I was first in line.
If you go to bucketheadland.com and scroll a bit you'll see some folks who did stick around and also a nice thread about "anyone going to see Particle" that'll give you a better idea of what they are like.
Have Fun! Try to get a toy! He's very prompt.