I couldn’t find any brackets when I got mine or anything that was close so I just bolted mine into the roof. Drilled holes through the roof, tapped threads in to match the bolts I have, then packed the hole and the bolt threads full of weatherstrip adhesive, as well as put it all on the underside of the basic mount the light bar came with. 1 year and several car washes later, absolutely no leaks. I went with a cheap 48” curved light bar off of eBay (solid white and solid orange, strobes both colors individually and flashes between the 2 colors as well) and have about 2” of room on each side. You could probably fit a 50” curved, but don’t drill through your roof unless you plan on using a ton of that weatherstrip adhesive to prevent leaks.
Also put a bull bar with 2 7” light pods on, LED low and high beams and LED fog lights. Possibly the brightest envoy out there!!