The stock gas springs on my 2014 international 27FB were rated at 90 pounds. After adding a topper like you, they would no longer safely hold up the bed while accessing the storage underneath.
I found these rated at 120 pounds on Amazon
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
They fit perfectly with no modifications on our model. I had to use a ratchet strap to compress them for installation. They are actually a little stronger than needed.
Yours may need a different size? You will have to check the compressed and extended measurements.