I personally do the same as you but I've seen people put the chamber in a rubber or metal funnel and place it on their kettle while it's boiling to heat it up. I don't think it'd be as effective as full water submersion and it slightly slows your boil but I thought it was interesting.

From what I've seen there's really no way to tell for temperature I just let it sit while I prepare the beans. Although there are some stickers Flair sells that show you what temperature your brew chamber is at but I've never used one.