Wedding for friend -7D

A friend has asked me to take some pics his at wedding soon. Never having done a wedding before, I am doing this for free as a favour. The ceremony will be held in a hotel room, not a Church. I will be using my 7D with 24-105 L lens using 420ex Speedlite. I would welcome suggestions as to what settings I should use, especially ISO. Most of the shots will be of an informal nature.
I also have an 85mm f2.8 , but have a preference for the flexibility of the zoom lens.

All suggestions/comments are welcome.

Inside go for ISO1600 or 3200. Outside use whatever you like. If you're using a flash inside bounce it from the ceiling or a wall, high ISO, shooting manual. Outside point it direct as fill.

You will not have no problems with the 7D, but watch that ISO, 7d's are not that forgiving with noise. As for what setting to use, I only ever use manual and never shoot higher that ISO 800 on a 7d if I can help it. though with your 24-105 and being indoors you may need to go higher.
Unless you can keep your distance and use that 85mm 1.4
Don't forget you got IS so dont be afraid to stop down the shutter instead of increasing the ISO
Shoot in raw..
My only concern though not a deal breaker is your wide angle end, you could do with at least a 17mm on your 7d.

Take plenty of memory cards and batteries.
Good luck and please share with us your results.

Most of the time you never really know what your settings are going to be until you get there unless you scout the location and even then there are variables.

There are so many factors to consider. How many windows? How big are the windows. No windows? Are there curtains. Sunny day or cloudy day? or is the wedding at night?

If you need ISO 6400 on a 7D I would do it. Light-room can do a great job in post processing noise.

Thanks to all who responded to my query.
I have 8 days to the event, so will take some test shots in the meantime.
It will be in the late afternoon, so will all be indoors, with room lighting.
I will be happy if I can get some respectable shots, and will shoot in RAW, doing post with Canon DPP and Elements.

I would rent another lens (maybe the 17-55) or at least borrow the 18-55 for backup. If your 24-105 goes out, you dont have a lens wider than 7-, which is a HUGE problem.

Red Tie Photography wrote in post #13601413
I would rent another lens (maybe the 17-55) or at least borrow the 18-55 for backup. If your 24-105 goes out, you dont have a lens wider than 7-, which is a HUGE problem.

Good point. I can borrow kit lens from a friend just in case the worst happens.
Thanks for your reply.

Test shots are a great idea. Bring a person along so you can do a proper test

Watch your shutter speed very carefully, in our part of the world it can be very dark inside even during daylight hours when you get little light from windows.

IS lenses help a little with your own movement at slow shutter speeds but don't help a jot if your subjects are moving.

Whenever I have a second shooter work for me the only two things I ask them to focus on are hitting their focus point and watching their shutter speed is fast enough to avoid camera shake and subject movement.... if its not focused properly or the shutter speed means there's movement in the shot then there's not much you can do in PP to recover it.

I use the lowest possible iso when im under really good light(sun)