hi MO, sorry for the delay in replying.
You need to make the patches work in non mirror mode.
I would like to make seamless a bit more user friendly before I do a tutorial showing how to do this to avoid some pitfalls that can arise but it is not hard to do now if you pay attention to some issues. To make a patch work in non mirror mode, first select the patch by clicking on one of its control points. Open the selected patch's control panel by clicking on the 5th button in the upper toolbar. Unchecking the mirror check box causes the selected patch to stop working in mirror mode (allowing for non symmetrical modelling). This is easy to do but it is important to understand that many of the patches in a head will have a corresponding left or right patch that must also be unmirrored the same way, or you will probably experience later, an unexpected consequence of leaving one of the patches on one side in mirror mode with no corresponding patch in mirror mode when you drag one of the mirrored patch's control points. To be able to see the area a patch covers, temporarily check the showAll check box. If you drag a control point for a patch that has the showAll box checked, the mid points will not be automatically calculated, so you will probably want the showAll field clear when you want to resume dragging any of its points. Another unwanted issue, may arise when you insert a control line, if you have a mix of mirrored and non mirrored patches in your head. So it may be wise to uncheck every patch in your head if you plan to insert more control lines.