1) Magnet position on the back of the LCD in the PB G4 1 - 1.25 - 1.33 - 1.55 (1st gen). The HiRes LCD from the later PB G4 1.67 does work on the earlier PBs G4, but, given the different position of the sleep sensor (no longer under the trackpad, but along the front edge) the Mac does not go to sleep at lid closed. Unfortunately the different materials used for the new HiRes LCD do not let the magnetic field to reach the sleep sensor. So I decided to look for a more powerful magnet with a thickness under 2 millimeters (to allow the correct positioning of the display rear housing).

2) Finally I found a holder magnet that could be used for the project

3) Magnet (removed from the curtain holder) positioned on the back of the HiRes LCD, pulled from a PB G4 1.67 (2nd gen). On the left is visible the old magnet.

4) PB G4 1.5 GHz with the 1440 x 960 LCD!

5) Reason why Apple opted for another solution...

Please note the PB 100, behind, which is still fully functional.