Yes pot size is more important than one might think. Also, the soil
in the pot is important. As is humidity. People growing VFT in pots
with the soil level down well below top of the pot, 3-4 inches down
from the rim to create a higher humidity mirco-environment, have
gotten very large plants. Soil of peat:sand 1:1, or even a little
more sand is very good. They also like bright light, full sun so
long as they are not inclosed in a terrarium and bake.
I've seen some w/ traps getting about 2 inches long.
Dave Evans