I also like to use
150mA drivers to run Vero 10s. The driver is only $1.25 and it can run up to about 50.8Vf. It is 85-88% efficient and should be perfect to drive a pair of Vero10s (~24.7 Vf @ 140mA each)
@3Vf driver squeals and hates life, 30% efficient, 100mA output
6Vf, 58% efficient, 183mA output
9Vf, 70% efficient, 165mA output
12Vf, 80% efficient, 164mA output
15Vf, 84% efficient, 160mA output
32Vf, 85% efficient, 156mA output (CXA3070)
38Vf, 86% efficient, 154mA output
44Vf, 86% efficient, 150mA output
47Vf, 85% efficient, 146mA output
50.8Vf, 85% efficient, 135mA output (maximum Vf)
above that, the driver strobes