Last number of your post is how many minutes you must hold stance.
Use a broom handle over your knees. If you're not parallel and the broom slides down, you're not doing the proper stance. Feet must be parallel, pointing forwards, push the hip forward.
Yeah backwards anything is great for your knees. I do it at the very start of my knee work. Not sure if that's the best way to do it, but I just like to get it out of the way since it sucks so fucking much. I also feel like all the movements I do afterwards are a lot more comfortable.