Graduation for non-graduated measuring cups

Express composite sold me some nice PET graduated mixing cups. I severely underestimated how many i needed so about half way in i was forced to use non graduated cups that I filled using my last graduated cup. Way messier than I liked... On a trip to Wallyworld last night i found that they sold Solo cups made from PET also so i bought a bag thinking i could measure with the fancy graduated cups but mix in the reusable one. The regular white/red ones does not work since the styrene melts them PET seems to hold up well..

SOLO cups from Wal-Mart.

Made from PETE. 

What struck me was how well they nested so then i came up with the idea that i could use a graduated outer cup as a scale and reuse that.

I put a strip of masking tape on the outer cup and then i dropped an empty cup inside. Using a graduated cylinder i filled the inner cup to 50, 100, 150 and 200ml and marked each level with a permanent marker

I like to use ml since the syringe I use for the MEKP is also graduated in ml.

When mixing resin i drop a fresh cup inside the template cup and fill to the mark before lifting it out and adding catalyst.

150ml fresh resin...

After using most of it i left about 30 ml to harden in the cup and it seems totally unaffected