How to make a Gyroid in SW?

I almost did it, but I have a problem with thicken function at the end. It doesn't want to thicken it to both sides but just one. Maybe the is a problem with basic surface of Gyroid witch is made with function Filled Surface. That surface isn't toned to all the lines of sketches. I also think that it should be tangent transition between surfaces, but it's not, and i don't know how to fix it.

Later I manage to thicken it to both sides,  but the transition between thickened areas is not as smooth as it should be. And if I want to change radius in basic sketches, it automatically crashes.

Ps. Sorry for bad English!

Thank you for answers!