I want to know where the sweetspot is. I have a Yonex NS7000, with standard string, don't know how much weight.

Can anyone tell me?

Yonex marketing about Isometric heads and MegaFrame heads:

the Isometric Square Head shape together with the unique Mega-Frame design creates a 34% larger "sweet spot" compared with a conventional racquet. the Mega-Frame design stretches the already large "sweet spot" realised by the Isometric design, further outward in the stringbed for a faster swing speed, more repulsion, fewer miss-hits and more responsive off-centre hits.