I used exactly the same like your blue ones, just in black. Those were the largest mini-heatsinks I could fit on the chips. The ones that Bitmain used, however, are much better because they perfectly fit the copper area, and are even larger. My "green" miner, which features these heatsinks, is about 4-5 °C colder than the "black" one, which features black mini-heatsinks (photos in first post). Unfortunately, I haven't found the heatsinks Bitmain used for sale anywhere.