I tried to find this in the NADAC handbooks but can't. What is the minimum number of tunnels and what sizes does one needs for a show? Looking to expand my tunnels out to a full set for VT. I currently own 4 15' and 2 10' tunnels but no 20'. I know I'm short in numbers, I just need to know how many to look for.

Thank you!

-Amy and the schnauzers