Hi Ash,
I'm converting a Vitesse to wasted spark, I used a wheel from triggerwheels in Cambridgeshire. I have posted what has been done so far on the Club Triumph forum search "mk2vitesses" posts to see pictures.
I am having made some steel blocks to weld to the timing cover. Thses will form the fixing for an Alloy sensor mount.
They will straddle the centre rib on the timing cover, you will then need to drill the timing wheel in the right place!
I choose to put it there to keep it within the fan belt track, this will mean if the belt breaks it will not wipe out the sensor etc, it also makes changing the belt less hassle!
I have also seen the front pulley machined with the required teeth, this will save the purchase of a wheel!

I will give more details when they have been made, expected this week.
Simon