All hammocks have weight limits. They apply to both the body fabric and the lines, hardware and other weight-supporting items such as tree huggers or slap straps. IOW, although the manufacturer's weight limits are usually conservative, IMHO, the other load-bearing items have to be taken into consideration as well. Choose carefully.

The principles to keep in mind always are: when a system reaches its limit you should expect it to fail catastrophically; and use your system to minimize stress on it. For example, hang your hammock loosely - sagging- from its supports since that produces far less stress than hanging it tightly.

For homemade hammocks, you have to be your own engineer. For example, I use home-made hammocks of either 1.1 oz or 1.6 oz nylon and lines exclusively of 1.5 inch polypropolene webbing. I weigh 220. If I weighed over 300, I would use 2 inch webbing and the next available heavier fabric such as 2 oz.