LRB:

IMHO there are two way to bypass the TRC. One would be to replace the ignition system with an modern unit such as the Crane 700 (which I use) or the Pertec. Cost would be in the $100 range.

The other is to physically bypass the unit itself (as you asked).
I don't have either my car of any schematic here at work, but if you wanted to physically bypass the unit, you would have to run a wire from the output of the ballast (second?) resistor to coil(+) then disconnect the brown wire from coil(-) and the wire from the distributor (black or green???) to the TRC unit. Run a new wire from coil(-) to the point on the distributor where you removed the connection to the TRC unit. That should work. In effect, you would have a standard breaker point system. Only thing I cannot be sure of is the relationship between the Bosch coil and the ballast resistors but it should not hurt to have them in the circuit. Not sure if the Bosch coil has internal resistance or not.

I put the Crane on my 71 250C AFTER I did the Webbers and it made a difference even then. "Off idle" performance much better, quicker starts, less maintenance on the plugs, better idle (and the idle was pretty good when I put the Webbers on) and I have not had to reset the ignition timing in over three years.

Just my opinion here - "your mileage may vary"...

Dan

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Dan Taylor/ Tulsa, OK MBCA
'84 300D/'90 Jaguar XJ6/XJ40