Thanks for the answers, guys.
We actually cut out most of the cross beams on the trusses...All they were doing was adding more weight hanging from the rafters. We left one large truss in the control room, which is sturdy as can be. Where the others were cut out, we added rafter ties. Extra gussets were added on either side to all of the rafters. These rafters were made out of what is now 60-year-old slow-growth lumber...it's much heavier and probably twice as strong as new lumber. It was twice as hard to cut through, anyway...
I might get someone else's opinion (like a local engineer), but I am really not worried about hanging two layers of drywall on this ceiling.
