What are the measurements of the stone? I think you should stick to a G.I.A cert. reason being that if you ever want to upgrade or sell the stone it's more acceptable in the u.s.a and you would get more for it.
Why don't you check a few websites and see if they have a similar stone with a G.I.A cert.
as far as the make is concerned the ratio between the length and the width of an EC.diamond should be approx.1:1.5 length to width .
most of the sites are very informative and give you great deals ,and if you are not in the same state as they are you save the sales tax.
best of luck
The HRD cert. is very acceptable in europe, not as much in the U.S.A,.You would only have a problem later whenever you would want to upgrade,exchange or sell this diamond in the U.S.A
as far as the stone is concerned it is not to my likings but faint flourecense is not conisdered bad.