Consider a pair of gloves, a tool to break canopy and something useful for digging.
When my RV4 flipped, the roll bar did a good job of busting the canopy. Due to forward momentum, the roll bar bent and sunk into ground. I had about 3 inches between canopy skirt and the ground. Even if all plexiglass was removed, I could not get out. I prematurely released my seatbelts and landed on my shoulders. Then started breaking away chunks of plexiglas and digging with my hands. A difficult task upsidedown on your shoulders. Would have been better to dig hole before releasing seatbelts.
I thought I had a hole big enough to get out but ended up getting stuck. My head went through but not my chest. Luckily people in a near by house seen the crash. They came and lifted the tail of the airplane so we could get out.
What ever tool you choose needs to be easily accessible, and small enough to manipulate.