Yeah seems ok to me but I'm not the most experienced, here is a shot from last night at 600mm, one uncropped and then cropped:View attachment 11528
Here you go, that's uncropped on Sony 200-600mm on A6400 aps-c (300-900mm).those settings look pretty good. Using another rule of thumb - Looney 11, your ISO for that speed should be 500 for a decent moon exposure shot. That doesnt sound too bad but f/11, 1/250 sec and ISO 250 sounds a bit better, you'll get a chance to experiment and see what works for you. Shooting the moon isnt too hard, you can even handhold something as long as 600mm to take a shot and get away with it. My brother eliasfta shot the moon last week on a 200-600 lens, lets see if we can get him to post his shot here
View attachment 11579View attachment 11580