Wow, looks to be coming together nicely
If the port will now be downfiring, you'll want to make sure there is at least 8" of clearance between the port opening and the floor for optimal airflow. If the driver is now upfiring, you'll want to make sure the motor structure won't obstructed by the back walls of the eclosure, as it will be mounted at an agle if I am not mistaken. It's hard to tell how much depth you'll have to mount at that angle.
Lastly, you want a lot of thickness and weight on the baffle - if you are using 3/4" MDF, I'd go for no less than 3 layers. All these things kinda go to show why you rarely see upfiring drivers, but if you can pull it off, more power to you. Can't wait to see the finsihed sub.