Dry wall screws are best for installing drywall to metal studs. When working with 1/2-inch drywall panels, use 1-1/4 or 1-3/8-inch nails or screws. When working with 5/8-inch drywall panels, use 1-3/8-inch or 1-5/8-inch screws. In most cases, securing drywall will require fewer screws than nails. Coarse-thread of drywall screws work best for most applications involving drywall and wood studs. Wide threads of dry wall screws are good at gripping into the wood and pulling the drywall against the studs.
Dry wall screw were originally invented to hang drywall but are now used by many people as an all-purpose fastener. Dry wall screw can sometimes be used in place of wood screws but they do have their limitations. Vice versa for wood screws. Dry wakk screws over existing walls is very similar to hanging drywall in a new construction setting. The most notable difference is that you can‘t see the studs to know where to put your screws. The screws should only penetrate the wood 5/8 to 3/4 in. Any deeper and they’ll be prone to popping later. For a speedier job, take a tip from the pros and tack the perimeter of the sheets with several ring-shank drywall nails to hold it.
Your drywall should end on stud or be butted up in the center with another piece of drywall. Either cut your drywall or add more studs. There is absolutely nothing wrong with 17-19″ on center which sounds like about 3 studs per sheet. I have run into this with old houses