I was going to post..but I see you already found my thread on the Hakko
There is no way in heck I could have done the last batch of GPU's without it.. they were a newer revision..without a solder bump to land to! They had only a small gold pad..not very solder friendly, but with some .025 rosin core and ~40W's..everything came together just fine.
*I like silver solder the best, as I feel it has superior resistance to corrosion..however it is difficult to use for GPU mods, as it requires a lot of heat to bond properly. While it will melt with ~25W..it needs ~40W to bond.