Pi3 backshell with air vents

I built the original version of this screen and backshell combo, but I believe the Pi or the 1000C overheated and kept re-booting the Pi. Everything felt too warm, so I did a remix of the backshell with a bunch of air vents added into the design. It appears to have solved some of the issues.

A larger problem for the build I've made is that the Adafruit 1000C converter is NOT adequate to successfully power a Pi3 B+, let alone the Pi along with the 7" display screen. Apparently the 4 cores on the Pi3 B+ present a widely variable load to the 1000C, and it just cannot cope. So I am looking for some options there.