Help with a joint...

[Gideonn]

First and foremost i must say I'm not a carpenter and do not really know what I'm doing so  math and angles are likely completely wrong I'm guessing at this point... I'm posting to try to get some assistance w/ these numbers and how to do what I'm trying to do. Any assistance you can provide would be greatly appreciated.

I purchased the master system and am trying to use it for a project and need some help... I'm making something similar to a breadbox but want to make the joints as smooth as possible. Instead of using a 90° angle at the back I want to do a compound angle.  I'm using 3/8" Red Oak as the material....

 

So I want to do the back two corners like this:

______
/ --- \
| - -- |

Instead of like this:

_______
| ---- |

With the bottom of my drawings being the doors. I'm thinking the easiest way to do this is a ~45° angle at the back two corners but 1) I'm not sure what angles I need to cut these at to have this work the way I'm invisioning it and 2) if I do this if I will be able to use the jig/screws the way I'm invisioning it. Basically I'm trying to hide the edges of the wood so the box is nicer looking. Any help is greatly appreciated.

Thanks,
James

 

PS. I've added a Sketchup draft w/ an approximation of what I'm trying to do.  Please let me know if there are any questions.