Ok this how I did mine. Maybe you can improve it.

1. After opening the head, I removed the screw holding slots on the back of the head (GREEN CIRCLE) completely. Shaved it down until smooth. The two on the inside of the head (GREEN CIRCLE) I sniped short.

2. The RED OUTLINE SQUARE is were I placed the Battery compartment that I made. It is composed of 1mm pla-plate. Ive added the size of it, but I dont remember the height. Its basically the size of both CR1025 cell button batteries on top of each other. The ORANGE circle is a copper contact that is on both the top and bottom of the compartment. RED and GREEN coming out of it are NEG and POS wires.

3. The 2 smaller RED SQUARES are the SMD LEDs (WHITE) and the BLUE SQUARES are 180ohm SMD Resistors. I wired them up as in the picture. GREEN for POS, RED for NEG. Before gluing down the LEDs I scratched a bit of the silver paint away so the light shines through more.

4. The YELLOW CIRCLE on the back of the head, I filled it in with putty, made smooth and painted it black.

5. The PINK Square is where I cut out the back and placed the SMD on/off Switch. I even showed how to wire it up. On the inside the 1st + and - is for the wires from the batteries. The 2nd pair of + and - is for the LEDs.

6. I then painted the back of the LEDs black and placed electrical tape over it so the light doesnt shine threw the cracks.

7. Putting it all together I Super glued the top and the two places on the botton. NOT the whole thing. Its so you can open it again with ease.

Note, I did not glue the batter compartment down. Its so you can move it in case you need to change batteries.

If you have questions, LMK.

It took me roughly a day or so if you add up all the hours. But since I had to wait for the batteries to arrive it took a over a month.

Good luck!