However, I don't think this will do 100 Flat, Main reasons.
A. The orange trigger catch I believe might be inferior to the white plastic one on the Retaliator.
B. The wire used to connect the pump handle to the bolt sled probably would bend past 5 Kg's of spring just like a Raider, Rampage, ect.
5 Kg's should be fine, be sure to use a stronger trigger catch spring and mod at your own risk.
See you in disneyland.