Xue Sheng
All weight is underside
It's not static for me & mine. It's dynamic. You have to move to use a stance. If you go only completely static, you are incredibly rooted. However the downer is that's all you know. Likewise if you never root, you may be quick as hell, but a strong wind will topple you. You have to learn a moving root. You can't do it standing like a statue or moving like leaf in the breeze. It's a mix of both. At first more static than not, but then it needs to equal out.
Your milage may vary...
Becoming double rooted is always an issue and I will admit after much standing in Santi Shi I came to the conclusion that ultimately you need to me able to move that and maintain structure and root... oh and be relaxed too.
I use to be a big proponent of standing in Santi at least 20 minutes per side, which is light on the Hebei side and heavy on the Shanxi side of XIngyiquan (I was Hebei). But I ended up with ten to 15 minutes was good but you had to know how to move that and maintain it and I began to feel moving was better. But it is much harder to learn the structure when moving so in the beginning of Xingyi training I still recommend at least 15 to 20 minutes per side, but never forget this needs to move and move fast