I made a watchface which shows the altitude beside the time.
The watchface can be found here
For polling I used a dynamic management between 5 and 256 seconds. If it reaches the longest sampling period it shows this on the screen. Usually it means that you are indoor and the phone's GPS doesn't get new data but sometimes it indicates also that something with the phoneapp went wrong. (Didn't figured out yet how to read the error_msg from httpebble.
I'm glad to share the source code with you but as I don't use github or have a public dropbox folder you need either to send me an mail or tell me where I can upload. Any how as I have really no glue about programming it's probably better not to publish it.
It's a little bit a pity that we don't see more app's using httpebble as it's quite powerful and open a lot of opportunities.