i would go with .025 unless you have smaller . i would imagine thats the smallest wire your machine runs, as does mine. you can also buy stick on heat sink to get rid of some of the heat. as mentioned above with the rags.
belive me it will be very time consuming. you may also try in your practice welds turning up the gas flow a little. since you are not making structural welds you could probly weld a little cooler and have no side affects. (try it with some scrap first)

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