It does look like a nice flute. I've broken enough doing flutes that I try to make it a last resort to remove thickness. When it works it's great, but I do it with some trepidation, especially on obsidian. Just did it on a Keokuk piece and pretty much wimped out on the second side. Been working on my thinning from the sides at the base. Need to cook some rock, then I wouldn't have to hit so hard. Good luck on your rock crushing. I can see improvement there, don't get discouraged. Need to get my tarp back out and make some more gravel in the shop.
George