This is a Wedge Box for the Adafruit PyPortal. It is set at a 15deg angle which works well. There is a parameter in the Fusion 360 archive (attached) that can adjust the angle. Values from 5-20 work well... smaller and you might have to adjust the ATMakers.org text and larger will require some fillets to be added for good printing (not a big deal).
This will be used for several projects in the ATMakers.org world... including a speech generating device.
The only trick is to get the orientation of the base right. On most angles, you're fine printing with the bottom of the base down. If you set the angle too high, you'll have to add supports and maybe tilt back the box.
Your mileage may vary.
On the top, I've had success printing it face down. Better results may be found by printing it vertically with a raft, but I haven't had time/need for it.