Length: 12.19141 m
Size (fully grown): 6.675 m tall and 16.8973 m long
Now to find the current I. rex was before being fully grown.
(12.19141/16.8973)*6.675=4.81602 m (current)
4.81602/(448/116)=1.2470052 m
1.2470052*(453/381)=1.48266 m
1.48266/(404/5)=0.01835m
1.48266-(0.01835*2)=1.44596 m
I’ll subtract the entire full volume of the Gyrosphere and subtract it with the volume of the air to get the volume of the shell.
(((4/3)*pi*(1.48266/2)^3)-((4/3)*pi*(1.44596/2)^3))*10^6=123616.01263 cm^3
The glass of the Gyrosphere is said to be bulletproof.
Fragmentation value of ballistic glass: 32.41 joules/cm^3
32.41*123616.01263=4006394.96934 joules
4006394.96934/1000000=4.0064 megajoules (9-B, Wall level)
Update[]
It's stated in the Evolution of Claire book that the Gyrosphere is made of a material (aluminum oxynitride glass) is supposed to be stronger than any steel so it would stronger than damascus steel which has a fragmentation value of 814.5 joules/cm^3. I goofed up not mentioning that it was shown to have needed to shatter it by fragmenting it 6x (smashing it against the ground 5x and cracking it with its jaws).
814.5*123616.01263=100685242.287 joules
100685242.287/6=16780873.7145 joules
16780873.7145/1000000=16.781 megajoules (9-B, Wall level+)
Update 2[]
So half of the volume of the glass was shattered to pieces as shown in the feat.
16.781/2=8.3905 megajoules (9-B, Wall level)