I've just fitted this setup to a N/a block I am building. Same issue with the bolt hole. A bit of extra sealer and it should be fine.
Ideally you want 60-2 trigger wheel for more accuracy, but as there is no bolt on kit for Starlets the whole crank sensor setup can be a bit of a carry on. I'm waiting on a 60-2 wheel being fitted to an alloy pulley. Then there is still the issue of a sensor bracket to get perfect.