First of all, I want to thank you for this amazing mod. These are some gorgeous thrusters that should be included in the vanilla game. Unfortunately, I feel like they are not well balanced.

Vanilla blocks are balanced according to size: more powerful blocks require more space. Therefore, the smaller size of the small helicarrier thrusters should mean that they have less power and require less components.

I would suggest making the small thrusters have 1/3 of the power and components of the vanilla large atmospheric thrusters.

Additionally the thrusters could be made stackable. That way ships with thicker wings can have a little extra power.