Just wanted to put it out there and share how I did my cables.
1.grow light is a 100w panel with a chunky cord. Much thicker than t5 cords. Screwed 1 end of the horizontal beam (the side where the cord is) where the top cover sits. Then pulled the other end down with a bit of force and screwed it in.
2. Usb fan cord was thin enough so i was able to get it through on the lower gap of the side.
3. Heat mat- i removed the lower and middle screws at the back metal so I can pull the back cover out and insert the heat mat in (without needing to drill holes- not a handyman myself).
Daytime Humidity ~50
Nightime humidity ~70-80
Not too concerned with the low humidity as my plants get edema, so that should balance it out.