Help me clashers

For players using a Duke Charge with Electro Fang into Root Riders, which equipment would you upgrade next?

Current levels:

- Electro Boots: 20

- Rocket Spear: 23

- Action Figure: 23

My usual attack is a Duke Charge with Electro Fang followed by a Root Rider push.

Would you upgrade Electro Boots first, or would Rocket Spear/Action Figure give more value at these levels? Looking for advice from people who use similar Root Rider armies.