Hi Wanzo-
I don't want to be a downer, but are sure you can handle this? There are portion size calculators available on the net, if you think you are up to the challenge. The soldiers returing home from duty worries me a whole lot less than a wedding. With the soldiers, they will probably be very happy with a BBQ meal. With a wedding, hopefully, that's a once in a lifetime event! The stakes are very high when it comes to catering weddings.
Have you also considered food safety issues as far as food cooking/holding temps and such? The right way to go about this venture would be to obtain a foodservice or caterer's license from your local health department, and to obtain the proper liability insurance coverage. Personally, I wouldn't risk getting sued without insurance coverage for the pofits that two jobs for 80 people each would return.
With all that said, you don't necessarily have to spend an arm and a leg to get a permit or insurance coverage. Most places will not let you cook out of a home kitchen for commercial purposes. Do you belong to a church that has a licensed kitchen? If so, depending on your locale, you may be able to use their kitchen as a commisary. You could just work out a rental agreement with the church, and have the health dept. license you using their kitchen. I've also seen bars that have abandoned their foodservice rent their kitchens out to caterers.
Again, I'm not trying to be a downer, but portion sizes and food costs are probably about #s 19 and 20 on the top 25 list of things to do when getting into catering. Those two issues are no less important, just other things need to be handled first.