Unfortunately, it's not possible to calculate the forces on a 4 bolt system from the angles alone. Please see my article on 3-point anchors for an explanation of why this is the case. http://rigriteapp.com/advanced-use/three-point-anchors/
Let me know if you're talking about a different kind of setup though.
I've updated the FAQ article on this. Have a look at let us know if that's the situation you're referring to: http://rigrite.uservoice.com/knowledgebase/articles/357371
Thanks for the suggestion. This is definitely something we'd like to add to the tablet app. I think smartphone screens might be too small to make this practical though.