Do you mean Escallonia ?
If you do, i'd suggest double !
I planted these as a hedge 3 years ago and i wish i'd done it as double rows now because it makes a better hedge - in my opinion !!!

As for how far apart, what age and size plants will you be planting ?
Large 'established' plants - that's what i used. (they were 5'x5')
Or, small garden centre sized plants ?
If the latter i think the spacing's recommended at about 18"-2' ... but i'm not 100% certain .... wait for Bamboo or Doctorbob to reply because i think they'd be a better guide on that !

sorry about spelling,haven't got plants yet. supplier says they are in2 ltr pots and 40 - 60 centimeters high. Thanks anyway