1) Go to Seller Admin > Cart Shipping Settings;
2) Delete your zipcode, set custom (Domestic & Int'l) rates per oz. at 1.00;
3) Set the cost of a Large Tube at 9.00 and the cost of a Small Tube at 6.00 (both with weights set at 0.00);
4) Click Submit to save changes;
5) Go to Admin > View/Edit Products > Select product w/ $15 first-item shipping > Click Edit > Click Next to reach Shipping Settings screen;
6) Set Packaging Type to Large Tube, Shipping weight to 6.00, and packaging capacity to some absurdly high number like 9999 -- then click Next until you can Submit changes;
7) Repeat steps 5 & 6 for other products w/ $15 first-item shipping;
8) Go to Admin > View/Edit Products > Select product w/ $12 first-item shipping > Click Edit > Click Next to reach Shipping Settings screen;
9) Set Packaging Type to Small Tube, Shipping weight to 6.00, and packaging capacity to some absurdly high number like 9999 -- then click Next until you can Submit changes;
10) Repeat steps 8 & 9 for other products w/ $12 first-item shipping.