What are your 3D Maneuver Gear operating theories?

Alright people, I'm both bored and stumped...I'm here trying to figure out the exact mechanics of the 3D Maneuver Gear. Now, I've got some theories but I keep hitting speed bumps and inconsistencies; the best I have right now is:

1. The Upper Switch- I believe this is the attach and release mechanism for the blades

2. The Lever - I think the hand-brake looking lever may be the throttle

3. The Top Trigger - Obviously the firing mechanism

4. The Bottom Trigger - I have no idea what this other trigger is for

After posing this question to my friends, one of them suggested this as the possible control configuration:

1. Top Trigger: Firing mechanism

2. Bottom Trigger: Retraction mechanism

3. Handbrake/Clutch Lever: Cable tautening mechanism

4. Upper Switch: Blade lock and release mechanism

Most recently, I found a cosplay design that has the lever is the firing mechanism and the top trigger is the retraction mechanism but ignored the upper switch and left the bottom trigger out.

Ordinarily I wouldn't bother anyone with this question (I'd just let my wheels spin until I either figured it out or got bored with it) but this technology is so fascinating. What do you think?