Timing check

How do I check and adjust the timing of a Celica 2000 using a timing light?

There seems to be no way to connect or clamp it onto cyl 1 spark plug lead.

So, I tried it on the red/black lead from the ECU) to the ignition coil on cyl 1, but the pulse is not strong enough to set of the xenon lamp.
Yeh, yeh, I know, timing lights are "old fashioned", but I wonder just how one does it without a scanner.
Any ideas are most welcome.