I may have this wrong, but it sounds like you have completed a long pineapple & want to add color to it. Typically interweaves are done one of two ways. Either to fill areas that are larger ( over buttons, swelled areas of nosebands, ect.) or as the last pass of your button. If you have complete coverage you can either pull your final pass & replace it with color or do another full pass, for instance if you finished with an over two under two, go to over three under three ( this will make it larger). If your trying to go between something with full coverage it will probably crowd it too much, ther are ways to put in thin strands or some use horse hair, but I can't give a good explanation of the steps. Hope this helps, I'll be interested to see what others think on this as well. Buck