How do I make my (custom) landing legs hold up the weight of my craft?

In itself it is relatively easy, to make your custom landing legs use Struts, it is not necessary to modify anything, of course, the side actuators are a good option they support a lot of tons, (10,000 to maximum 50,000 kg) although it will depend on the length of them so that your engines do not collide, you can check my landers, the force-ratio relationship trick strength-weight are on the legs. Specifically on actuators.

@seventeen Not really useful so if you don’t just don’t comment it

Also one thing that might help is setting the stability modify up in think.

There is this thing in Tinker Panel you can mess with to make it invincible. Set part collisions to none.

no idea