Smaller setting for higher set stone, larger setting for lower set stone?

[DoeEyes]

I'm discussing my setting for my upgrade with the online jeweler. New stone is a .875 and I'm ordering an empty setting and have it set locally. I mentioned it would be great if the setting could be made so that a wedding band can sit flush next to it. The jeweler said they recommend a .75ct head if I want the diamond set higher and have my jeweler stretch the prongs when setting, or a 1ct head if I want the diamond set lower. I feel like it should be the opposite? With a larger head there would be extra prong length so it would sit higher. A head sized for a slightly smaller diamond means the prongs have to be stretched outwards and will sit lower. Right? Or am I confused?

 

[EC8]

Assuming it is a peg style head then the jeweler is correct, the head increases in diameter the further away from the band, so if the head is for a smaller stone it would have to be set high up on the prongs if your stone is larger than quoted size.

 

[DoeEyes]

Assuming it is a peg style head then the jeweler is correct, the head increases in diameter the further away from the band, so if the head is for a smaller stone it would have to be set high up on the prongs if your stone is larger than quoted size.

Ohhh thank you! Yes it's peg style. Ok so if I want it set higher to allow a ring to sit flush, I should go with 1 CT size head for a .88 stone.

 

[DoeEyes]

Nope, I was confused again. 3/4 ct head size for higher set.