The OEM mast and boom on a GB is rarely strong enough to lift much weight and the boom is rarely long enough. A proper davit would be much better.
Or, you could replace the OEM mast and boom with a setup that is actually useful.
I had a Sabot when I got my trawler. It was built to the racing rule, which mandated that it had to weigh in at 52 lb, minimum, all sailing gear aboard. Mine was within ounces of that desired weight. I would win every race in it. I tried lifting just the hull onto the back of my trawler, using the OEM mast and boom. Couldn't do it. First, the boom was too short, and only protruded out over the side of my boat by a foot or 18". Second, when I had a helper holding the Sabot off the side of the boat, the mast step broke off with the puny weight of the Sabot suspended above the water and all came crashing down. Luckily no damage to the Sabot.
A serious redesign followed, which I have detailed in another thread recently. I now have a mast and boom that work. They also look a lot like the original, and hold up my radar as well, which the original didn't do.
I can lift my Laser, have done so many times, even when there was a lot of water inside its hull, so I estimate I have lifted 300 lb successfully.
I have a much heavier dinghy, that lives on a pair of proper davits, designed for its load, on the transom.