Matrix p/o and tax issues

Has anyone come across these two issues and/or resolved them;

1. I can see that after creating a matrix item you can change the tax on the purchase side of the child item but not on the sales side. This is an issue for us as we sell shoes that cross from child to adult sizes where the former has no tax applied to the sale and the later does. It just seems strange that you can adjust the purchase tax code side but not the sales tax code in the child items.

2. When purchasing we order a bulk lot of an item where we cannot select the number of each colour when ordering. But we sell that item with colour options. The way we would like to purchase is to have either the parent item or the child item with no choice displayed on the purchase order, but then to be able to assign the quantities of each colour when we recieve the goods. If this is not possible does anyone have a viable work around.