Share 'How to LOFT?'

hi everybody, I have to grids with two different Z components and a circle is assigned to each point in each grid.circles in each grid have the same radius but the radius is different in each grid. i wanna loft each circle in 1st plane to its similar circle in the 2nd grid in orther to have a conic shape, but when i use LOFT, it goes wrong. how can i use LOFT here?