I looked last year to find him some little metal ones that he could paint up & would hold up to a few more years of play, but I couldn't spot any! We did locate some little wooden ones that were pre-painted which we bought for his birthday. He's really enjoyed using those Civil War soldiers alongside some paper ones he had, but I still hold out hope for some little metal ones for him.
And yes, those soldiers are quite mini in size. His finger, holding it still is practically covering the entire thing! One of the sets he picked was WW1 & the other was WW2. He's really eager to put a model together of a tank or WW1/2 plane as well, but he's not keen on the idea that those are mainly meant to be looked at & not used. I think that's what drew him to the soldiers. All though he estimates that at the pace he's moving it could take him a month to finish them.