RE: size, the kingsnake was 50cm (~20in), the rattlesnake 30cm (~12in)
RE: photo angle...very carefully! HAHA!
Actually, the rattler was somewhat sluggish, and didn't react to my presence until I was leaving the scene. I was able to hold my phone directly above and lower it until I had a good frame. The kingsnake had already been 'discovered' by a USFS employee who was scouting for the recent controlled burns. He and I yakked for several minutes, and the snake just hung out patiently. That shot was taken from about 1m distance, but angled steeply so it seems like a direct overhead.
I'm not short (1.9m, 6'3"), and have freakishly long arms, so it's easier to get these kinds of shots.