I have heaps of the 1N4148 sitting at home, however Pascal doesn’t like them because they have a threshold voltage of 0.7V and may cause problems with switches not registering, whereas the ones he is suggesting have a threshold voltage of 0.3V ie more sensitive.

I suspect if everything is repinned the voltage is strong enough not to have a problem.

Even though 1N4148 have worked for me in the past - Pascal may have changed his design to suit the schottky diode method, so I'd probably follow his recommendation. He knows the GTB board set inside out.