Developers who want to build a domed stadium for the Oakland Raiders in Las Vegas vowed to zero in on two potential sites within the next month as they face a tight timeline to lock in a real estate deal, government approvals and the NFL’s blessing. Representatives from Majestic Realty and the Las Vegas Sands casino company told an oversight committee Thursday that they want to get their plan in order by January, when NFL owners who must approve any team relocation by a three-quarters vote are scheduled to meet. “I think the hardest part will be getting to the finish line on the land,” said Sands President Rob Goldstein. “Please be advised that we’re on it day in and day out.”