1999 Montero sunroof size

I need a favor. Will someone share the overall dimensions of their 1999 Montero sunroof opening? Everyone says huge or large in the search results I've found.
I'm working abroad now and collecting parts for a trip in my Montero through the NC and VA mountains. The goal is to run an RV fan in an ABS sheet that sits over the sunroof opening overnight.

Thanks guys!
The obvious next iteration of the idea is an acrylic sheet instead of ABS to permit star gazing in the space on both sides on the 14x14 rv fan.

The maxxair fan is 12lbs and fantastic fan is 10lbs per Amazon. Acrylic is slightly stiffer than ABS so I'm thinking 1/8" 24 x 36" can support the fan when it's sitting on all four sides by the sunroof/opening. The sunroof drops and slides so the gap at rear side will need something. Peel and stick weather strip will keep vibration down and slow down any overnight rain. The fan flange bolts to the acrylic sheet. I may run two cross strips, gasketed bolts, and wing nuts to secure the whole thing from inside so it cant wiggle around. All will be stowed inside before moving any road travel.