Blending Drinks

Hey guys, so I wanted to start blending smoothies - mainly ice, powder, and different add-ons like PB, oatmeal, or whatever I feel like having at the time.

I have never made a smoothie out of ice - I’ve only blended things with milk. Anyone have any suggestions as a good ice-to-other stuff ratio? Like how much ice should I use for a 16oz drink? Thanks!

And if I should be aware of anything else that would help, let me know.