Head over to blue nile as a beginning of a search. Or do it here. There are a couple of ways to decide. You could go to a Build your own ring site on sites like BN and I am sure the other vendors have them.
Or you could subtract the amount of money you want to spend on the metal--say 250, that leaves you with 950 dollars left for two studs. So thats 475 dollars a diamond. Head over to Whiteflash and get an idea on a branded guaranteed high quality cut as a benchmark for maximum reasonable price for a diamond with guaranteed beauty:
I ran a search for D-J color VS1-SI1 clarity .2ct-.6ct ACA round diamonds, and the cheapest offer is .31 H SI1 for 521 dollars without a PS discount, So I think if you get the PS discount you can get it fro 495.
Meaning you would have to go over your budget and could get these two ACA:
4.42x4.44x2.68 $495 Whiteflash
4.45x4.47x2.73 $527 Whiteflash
Both of them ACA H SI1''s. I didn''t
Thus if you raise your budget 70 bucks and wire transfer the money (though you might have discounts via your credit card as well) then you can get guranteed beautiful cut of high quality at the cheapest price of 70 over and the maximum size of about 4.45mm-4.5mm
Now if you want to get an ideal/excellent cut lets head over to BN where I have found they generally have the cheapest small diamonds, but unfortunatly their studs are bit more expensive, asthey dont have the 150-250 dollar studs like WF has, they instead are going to run you about 350. Thus lets subtract 100 from your diamond budget and that puts you at 850 for diamonds, so 425 per diamond. This will be a bit easier now as they allow you to search via price very easily--here the cheapest diamond that they have that is AGS 0 cut is
4.22mm (.28ct) G SI2 for 346 dollars. and in the price range you have listed most of them (probably in order to match) would be about H-I color SI1-VS2 clarity.
Now to get an idea of the maximum ct available at 70 dollars over your budget (to compare with the ACA at 70 dollars over) is going to be .36ct at 4.6mm H SI2.
Thus it looks to me on a preliminary search that your best bet is going to be to stick with a vendor that has cheaper earring settings like WF that will allow you to get a very comparable stone of guaranteed cut quality and performance for slightly over your budget. However, if you went with unbranded options you could get it down to your budget.
based on my search at BN where a .34 ct H SI1 cost 474 dollars and a .31ct H SI1 cost 433 you could probably find an unbranded diamond at one of the other PS vendors with more service available than BN and get an equivalent stone to the WF diamonds for just at your budget in the .3-.34 ct range or you can go 70 over and get the guarantee of WF ACA.
but that was an incomplete search but I suspect those are your max and mins listed above 333 for .25, 433 for .3, 475 for .35cts of ideal quality and, .31-.34 at 500 a piece for ACA.
with the WG 3 prong martini settings, it would be around $100 over your budget. If you are patient and keep looking, you may be able to find SI1's that fit your budget.
I''d recommend WF for studs because they have good matches of ideal cut diamonds. I think you can go as low as H-I in color and SI1 and have a terrific pair! Just do the search on the WF site under ACA and then Expert Selection.
I got my studs at Mondera. Their prices for the settings are less ($250 for plat vs. $325 at Bluenile; $150 for WG vs. $185 at Bluenile). But they also have less inventory so nothing was jumping out at me to give you the most bang for your buck.
BlueNile has a pair of 0.64ctw H VS2 AGS0's for $1060 and a bunch of 0.60ctw below $1k.
JamesAllen has a pair of 0.70ctw I VS2-SI1 H&A AGS0's for $1150 (but one is 0.34 and one is 0.36, so I might worry about size difference).
I'm not finding a lot paired together by vendors so I'm going to try to find my own pairs. I imagine it would be pretty easy to contact the sellers about pairing the stones.
By searching by cut and putting different vendors' stones together, I came up with:
White Flash: 0.316 H SI1 ACA and 0.331 H SI1 ACA for $1022 with PS discount
(Sorry if somebody linked those already; I can't figure out how to search for pairs on their site.)
Their diameters are close so I think the size difference is negligible.
Good Old Gold has some pairs in that range but they're out of your budget.
Mondera: 0.34 I SI1 GIA VG HCA 1.8 and 0.34 I SI1 GIA VG HCA 0.8 for $926
(My earrings are GIA Very Goods instead of Excellents but with good HCA scores, and they are beautiful stones that give me a bigger spread than I would have had sticking with traditional ideals.)