I bought some awesome little pocket-sized spray bottles and roll-on bottles off an eBay store (can I

post the link?), that are perfect for putting in your pocket and taking out with you to "freshen up" or to

experiment by starting the night off with no mones and putting some on mid-way through the night.

Anyway, I

figured out what dosage I'm getting from the spray bottles/atomizers by just figuring out how many mL they hold,

then filling it with water and counting the sprays until its empty and dividing.

But the roll-ons I'm not so

sure what to do with. I know how many mL they hold, but is there a formula to calculate how many mL/inch they will

give you based on the size of the ball? (It's much smaller than the one on the SOE roll-on bottle.) Or would you

just fill it with water and roll it on skin or paper or something until it's out? Also, is it going to make a

difference how viscous the substance is? Like, would more water come out per inch, since its less viscous, than,

say, oil or an oil-based product like SOE, since its more viscous?