DIY : How to attach pergola on the terrace of the flathouse.

Hey guys I need some advice.

I'm living in 5th floor of the flathouse, the last floor. It's basically a small penthouse. I have 48m^2 terrace with floor construct of PVC welded hydroisolation and concrete tiles on top. So I cannot drill to the floor but I can remove the tiles and replace it. Permissed static load of the floor is around 400kg/m^2

I want to buy a freestanding pergola with rotating slatted roof (is it correct term ? ). The pergola is expected to be 3x4m with 143kg weight. Snow static pressure is 0.7-1 kg/m^2. Wind speed <50km/h mostly W-WSW-SW flat orientation S.

Could you give me an advice how to attach pergola to the floor with requirements above ? Is it enought to, for example buy 60x60cm concrete tiles, put two on top of each other and screw the legs of pergola to it (each leg 2 tiles)? I expect that I have to add some weight to it so its not gonna move by the wind.

Is there any rule of thumb how to estimate an aproximate weight of the open construction to be stable in winds ?

The companies does not want to do anything. Drill or GTFO.

thanks for any advice