Hi - So I'm trying to design a cross for home use - using 4x4 - but realized that there are a bunch of questions I have about specific design issues. Perhaps folks know of a source that can help with this, or can offer some thoughts about these questions:

1. In a lot of clips the 4x4s are set so that the cross is flush. This looks elegant, but as I think about it, what would be the effects of:

mounting the cross piece behind the upright - this would pull the wrists back, forcing the chest further forward;

mounting the cross piece in front of the upright - this would position the torso forward relative to the feet, perhaps making it more difficult to maintain an upright position.

1. What height / angle should the crux be? Is there any kind of formula? Should the victim be able to stand up straight, or should the crux be high enough that full leg extension is not possible?
   Appreciate your thoughts!