Advice for my first awards shoot!

I have been asked to do a shoot (as a favour for swimbo) to cover an award presentation for a 40 year service (within an amateur orchestra).

She is also asking for some shots of the orchestra practising.

I am not going to be able to see their practise hall until the night(Monday) so im wondering what i need to watch out for and any useful tips regarding flash.

My setup is 400D with Sigma 18-50 F2.8 EX DC,70-300mm Sigma f4-5.6 APO DG macro and Sigma 500 ST. I have a tripod as well.

I really dont want to make a mess of this (as i will get hell for months if i do!)

Flash probably won't help much, in such a big venue you might want a few slaves studio strobes if you're trying to light everything, but that'd be very distracting. I'd probably go with high iso instead. Use the flash if you're shooting one person getting an award, but meter the background so it's not a black hole.

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