Laser PIC fix for PS2 V9-V11

Everybody knows that PS2 models from v9 to v12 aren't the most reliable machines in the world. People tried to develop a solution to prevent laser coils from burning out. Comsoft fix v4 is the most reliable fix to my knowledge. I think it saved my own laser, by shutting down my moded v12 PS2 while it was trying to launch a game (to add to add insult to injury it was an original game just from another rigion! )

Anyways, the problem is that there is no working fix for an older FAT machines. romeo fix must be a joke and I don't understand how could it save a lens.

So, the idea is try to install a comsoft fix for v12 on a Fat PS2. I think it might be possible, because v9 and v12 aren't really that much different judging by service manuals.

So, I downloaded service manuals for 70000 and 50000 series and tried to figure it out. Unfortunatelly I don't really know much about PS2 hardware. It also feels like I don't have a right monitor to do this work efficiently (boy, an expensive 5k imac would've been quite handy).

Here's what I found so far.
Ground point - easy, it's everywhere. We may use USB-ground like in original mod or just solder a wire to the side of the motherboard.
J point (reset) - see attached picture.
K point (int) - see attached picture. I'm not sure which side of the resistor we shoul solder to. I think it will be easier to check it with continuity meter. Alternatively we may solder directly to ic605 leg 78. I would like to avoid it though, cause soldering to a resistor is much easier and safer.
5v point I'm not really sure about this. We might use 5v from USB, or we could look for a point that better resembles 5v point from original mod.
L1 and L2 I'm at loss here. Could someone experienced with PS2 hardware help me with this? Someone like l_oliveira maybe?

Please, check my findings and help me find remaining points.

Links:
Diagram for original mod
http://sksapps.com/diagrams/ps2/laserfix/comsoft/Comsoft-SlimlineFIX_V4.jpg
Thread with original mod description and a hex file:
http://psx-scene.com/forums/f110/comsoft-fix-v4-blue-led-out-35724/
My findings:

 

After what felt like swiming through a sea of shit on old psx-scene forums I finally discovered something usefull. Turns out one of the Ls should go to pin16 of LA6508 and the other one should go to mechacon pin15. Instead of cutting a trace we could lift a pin16 of LA6508.

I think I'm going to try to do this mod this weekend.