I used this stuff...
http://uk.rs-online....oduct&R=0567806
That did 2 bikes with a bit left over.
I think any tape with the "3M Scotchlite" brand name will be the same as mine.
The front one has tape around individual spokes..difficult to see when spinning.
I'd love to take credit for the idea but this has been done before and as said previously, you can get 3M spoke reflectors already made for the job.