I'm trying to create a hopper with different diameters and centres.

First you'll want to create a boss extrude of the upper straight section, the solid body only not hollowed out.

Then you'll want to create a reference plane to draw the end of your hopper, again this is just body before hollowing it out.

Third create a guide line that connects the outside edge of the bottom of your first body to the outside edge of the new sketch. You can do this by setting the endpoints coincident with the faces and setting the correct length.

Next create a lofted body between the bottom of your first extrude and the new sketch.

To hollow it out sketch the circles that represent the desired inner diameters and connect them with a guide line as in step 3.

Create a lofted cut using your two new sketches and your guide line.

You should be done!

Here's what I've done so far.