I'm not certain if classes act the same way as a form, but I tripped over the fact that if I "cut" a control from a form, and "paste" it back, it ends up as the last control in the list. If you wanted to get the order "right", you can "cut" and "paste" the controls.
The only reason I might go to all of the trouble is that on some of my scrollable forms, the controls with the lowest tab orders appear on the property sheet at the top. I'd never do it to control the order of instantiation.
HTH
Mike