Hey Chris!
I actually chatted with you about this project a bit at ElixirConf 
I have borrowed quite a bit from the world page speed repo in setting this up and I massively appreciate your responding here.
So the size of the app image is 1.08GB. I got that by doing fly auth docker and then pulling the image locally. Not sure there’s another way to see it. Is that a lot?
The actual machine boot time is pretty snappy. I get this message in the logs when I do a cold start:
Machine created and started in 3.514s
But then after that it seems like it takes another ~10 seconds for it to start handling the request. Is that to be expected? WPS always seemed faster to me.
The request processing itself takes about 4 seconds, which is ok and has as much to do as the site being tested as anything else. So the total cold start round trip is hovering in the 18 second range.
Seems like the most likely solution down the road will be to just keep at least one BrowserRunner FLAME node warm at all times.