Re: stones in contrast with red
It depends on your outfit. For my wedding jewellery I didn't want to go with the whole 'matchy matchy' look, and also as I don't often wear red didn't want to get lumbered with a red set that I wouldn't wear as much.
So I designed the outfit based on the jewellery - which I'd fallen in love with and bought. My outfit was red, with mustard and purple boarders. My set was citrine, amythest, rose quartz and diamond, which contrasted with the oufit perfectly and at the same time didn't look too out of place.