If you get something made up, remember it needs to have the missing teeth for reference, I have 280-290 missing from memory
Mine is a 36 - 2 wheel, also you need to make sure that the wheel is balanced and not too thick as it will foul on the front timing cover
I used 6mm but I put mine on an ATI balancer but measure your own
Are you using a Ross trigger kit? Ensure the wheel runs directly over the sensors, around 2 mm spacing mine is from memory.. Too close or too far and it will not work properly.
It's a big job man