Midday till late, indoors, 60th birthday - cheap 18-55 for the f/3.5 or 18-200 f/4.5 for zoom?

[Ezookiel]

I will be taking some shots today at an indoor 60th birthday party.
I'm torn between my own beloved 18-200 which I'm quite familiar with, or the cheap 18-55 that came on my daughter's 1100D for it's slightly larger aperture (max f/3.5 versus my lens's f/4.5).
The larger ap might help with the low light indoors, but then I'll be using the 430ExII as bounced light, and the zoom on the 18-200 might help get more candid shots as I won't be quite so in their face to get the shot. But that would put them outside the effective range of the flash to a degree too, so again a larger ap would be good.

I'm thinking I'll carry both lenses, and work from the 18-200 primarily but keep an eye on the images coming out of it and see if I need to change.
Hell, I could even carry my daughter's camera as a "backup" because I've actually been asked to do the photos for the day, so carrying two cameras wouldn't look quite as odd as it might if I was just another guest. Though I am primarily there as a guest. It's a surprise party for a very good friend.

I really do need to get myself some faster glass. It turns out most of the photography I do for others is indoors. My own glass is more related to landscape and outdoor stuff.

[WhoDo]

Sorry for the very, VERY late reply, EZ. I hope you went with the 18-200 super zoom today. If you're bouncing the flash then the slightly wider aperture isn't going to make a lot of difference. Hope it all went well. :o

[Ezookiel]

It was a bit of a late request actually. I really needed to ask with a bit more than 2 hours notice.
I carried my daughter's 1100D with the 18-55 as a spare and never used it, and just worked with the 60D and the 18-200, and apart from an early couple of shots spoiled by me turning the dial the wrong way, and setting ISO to "auto" when I'd meant to turn it down, and those few shots came out so noisy they were pretty much beyond use to my standard, the rest went rather well. I may have gotten a tad carried away though, as I took 841 shots - though I was working on the 3 rapid shots principle: - Take the first shot that caught your attention, the second shot they've looked up to see if you were shooting them, the third shot they laugh and you get a great smiling shot. Amazing how many times that worked. It also helps with the one person who manages to blink just as you take a shot, so with 3 shots you have a chance of them all having their eyes open in one of them. So with at least 3 of almost every shot, that's really only 280 shots.

Mind you, 280 shots is still a lot of PP to do. I'm sure starting to love the ability to record automation in PS and with just one or two clicks do the same thing to every shot - like the custom framing.

Thanks for the reply. Even if it's a late reply, it's still confirmation that I did the right thing.