We are having a company picnic in the parking lot in two days.  Myself
and 2 others volunteered to barbeque for our staff of 75 people.  We
want to cook 75 chicken breasts and 75 hamburger/cheeseburgers.

We will begin serving lunch at 11:30 AM.  We have rented a standard 5
foot "trough style" barbeque with an adjustable height grill.

Here are my questions:

1.  How much charcoal will I need?  What kind should I get?

2.  What time should I light the coals?  How long should I expect it
to take to be at cooking temperature?

3.  I was planning on buying frozen chicken breasts, thawing them the
night before, and then marinating 1/2 in BBQ sauce and 1/2 in a lemon
pepper sauce.  I was thinking of cooking them first and then storing
them wrapped in foil covered steam trays.  Is this a good plan?  Will
they dry out?  How long should I allow for?  How hot of a fire should
I cook them at (how high should the grill be)?  How long should I
allow for them to cook?  What time should I start them?  I have a
digital meat thermometer.  Am I correct that they should have an
internal temperature of 170 degrees F?

4.  I was then planning on cooking the hamburgers/cheeseburgers
starting about 15 minutes before lunch.  Is this a good idea?  I
figure ½ could be ready when people start to line up to eat and the
rest could come off while they are eating.

5. Any other recommendations?