I have no idea what the projected weight of this light is. However, FWIW, the completed SRK I modded into my version of DBSAR’s lantern weighs in at exactly 500 grams with 4 Samsung 30Q cells inserted.
It will not be a backpacking lantern by my standards. My guess is 1.5-2 pounds. I would love to see a nice lantern running off one 18650 or even one 18350 cell. For backpacking trips where I look to trim ounces off my pack weight I am always looking for tools that serve multiple purposes. With this is mind, I always end up leaving the UCO lantern at home and just adding a diffuser to my kit that fits the light I am bringing. I know that the light from this lantern will be much nicer than my diffuser tip provides, but sometimes sacrifices must be made.
For me, this will be a lantern for hunting and fishing trips and use around the house and cabin.