I've been closely watching Stingray prices for a few months. Ray's that are 'popular' colours have been going for less than the less 'popular' colours. Personally I don't care for colour matched heads, to others it's important. There's no real rhyme or reason to it, you've just got to be selling yours at the precise time a few people are looking to buy the exact model/finish.
If it were me trying to sell, I'd either put it up for £725 ono, or auction it with a BIN of £695, but I've seen matched headstock finishes go for £800+ - but that's really the exception to the rule.
Of the last 33 Stingrays up on ebay, only 6 of them sold, and they were:
£640 - Teal/Maple
£545 - Pearl Blue/Maple
£747 - Natural/Maple
£650 - Natural/Rosewood
£512 - Black/Maple (which imho was the best looking one)
£750 - Natural/Rosewood