I highly recommend a thermostat for the heat lamp, even this cheap one will be more than sufficient.
http://www.amazon.com/Hydrofarm-MTPR.../dp/B000NZZG3S
You really don't want any part of the cage getting above 95 degrees. it only takes 108 degrees to give a BP brain damage.
Instead of the locking clips you can always use bricks or pavers to keep the lid on.