water resoviour test rig

I made this test rig to see how big the refill hole in the water reservoir should be. Me, my 17yr old brother and my mum (who has bad eyesight), all tried to pour water into each container with each pouring device, (chosen based on what kinds of things I thought people might use to refill our design). We each selected which circomference size was the easiest/most comfortable for each pourer.

(The measurments on the labels are all the circumference, not the diameter, I wrote diameter by mistake) 

(above, common household 'pourers')

My brother
- drink bottle- 18/21cm circumference
-White pourer- 18/21cm circumference
-teapot- 18cm circumference
-Pirex- 21/18cm circumference

Mum (without her glasses)
-drink bottle-21/18
-white pourer-29
-teapot-18
-Pirex-29

Me
-drink bottle-21/18
-white pourer-18/21
-teapot-18/21
-Pirex-29

Overall the average 'comfortable hole size' to pour into is 18/21. We'll use this info for our fink design.