Another angle would be to indent a harmonic balancer the same way the crankshaft is and build a mount for the sensor.
You need to degree mark the balancer. Then precisely cross cut the indents.
The problem with this is the common problem of balancers spinning on the rubber isolator and throwing your marks off. You would also have to make a cover to keep crap from building up on the sensor magnet.
The other option I was talking about involves taking a 3.0/3.3 trigger plate that bolts to the inner part of the balancer and the timing cover is machined to clear it and fit a crank sensor. It has been 20 years since I had seen it done.