does anyone know which dimensions the 1.7 and 3.0 mm stand for? These are fairly hard to find in the US. Purchased a set from australia's ebay - 10 for ~$6. If anyone finds a source more local, please post. Searching USA ebay, one can find people selling 1-2 screws for $5-7. Also - I just called canon, and they 'discontinued the part number for the 790 IS'