Recommendations for flash in this building

What method should I use for this church as flash! - Diffuser?

I was asked to shoot a small wedding here for a friend and I am doing it for free for experience.

Any help would be great!!

I have 2 bodies the 40d will have my 17-55mm IS lens and 580ex The 30d will have my 70-200mm 2.8 IS lens and 420ex

Any advice would be great!

Here is a few pictures of the location

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# Exposure Time (1 / Shutter Speed) = 10/300 second = 1/30 second = 0.03333 second
# Lens F-Number/F-Stop = 28/10 = F2.8
# Exposure Program = normal program (2)
# ISO Speed Ratings = 266

For the overall shots, you can bump the ISO up a bit, & I'd white balance for the area behind the alter.
Where do you expect to be shooting from? have you talked to the priest?

General links:
wedding photographer needs lighting help

So, you got a new EOS and wanna shoot weddings

wedding photography inspiration - the master list

I am gonna leave AWB on and shoot in raw. I am thinking I am gonna use manual. Should I underexpose about 1 stop to get some ambient and let flash do rest? Do you think the ceiling is too high to bounce.

The B&G have talked to the priest and he seems layed back. I can shoot from sides and front but not behind. Flash is ok but not sure if its limited. I will be going to the rehearsal.

Thanks for the links. I have done sooo much reading the last little while.

My first recommendations is...Ask the Priest! I have experienced that the Priest, Pastor, Rev., Rabbi may not want Flash. Maybe it was this particular Priest but he said, This is a Church of God, not a paparazzi side show! With that being said, others used their cameras and took some snapshots. Go figure!!???

Do you think I should just screw it and just fire my flash direct with the stofen diffuser.

I'd rather properly expose, or maybe minus 1/3 stop, & just kick in a tiny bit of fill.

Yes.

RAW, yes. AWB, NO! Too many problems with AWB indoors. Notice that the very last exposure in the 2nd group of tests was of a gray card.
https://photography-on-the.net/forum/showthre​ad.php?t=54281

And bear in mind that you should gell the flash to come close to the indoor lighting. These work well for that:
Rosco Roscolux Swatchbook $0.01 at B&H
http://www.bhphotovide​o.com …EG&addedTroughT​ype=search

A gel on your flash really does make a difference!

I am seeing a green cast in the photos with exception of some areas. Does that mean there is 2 types of lights?

Fantastic links PhotosGuy your material is fantastic.

I think i am gonna use Demb flip it bouncer/card. Range is somewhat good with it.