I've been following this thread closely and am curious to see what you'll pick in the end.
I agree with rockysalamander that between those two, your choice should be based on what style she would prefer, and how she feels about a vintage style and pre-owned ring. Some ladies really would not like the idea of a pre-owned ring. No one can answer that question for you about your girlfriend. Out of those two I personally would pick the ebay one for myself rather than the Tiffany because I like the style better and the Tiffany name is not important to me, but I may be in the minority.
I'm just wondering why you've totally ruled out James Allen? I think you can get a beautiful brand new ring in your budget that will be very similar to the ebay one, but you'll have peace of mind and a reliable return policy, just in case. It seems like you don't really want the hassle of dealing with private sellers, and being in Europe makes it a bit harder too.
I think either of these settings posted previously would leave enough room for a nice diamond.
https://www.jamesallen.com/engageme...-halo-engagement-ring-round-center-item-18301
https://www.jamesallen.com/engageme...ellis-halo-diamond-engagement-ring-item-53050
I wouldn't go with the one JA recommended for you, with the pave band, because it doesn't leave enough budget for the diamond.
For the diamond, you'd have about $680 to spend. I'm not an expert so I'd rather not post a suggestion, but if this is the route you decide to take, the members here will pick the absolute best choice to maximize value for your budget. From what I see, you can afford a bigger center stone than the 0.35 ct in the ebay ring.
I hope I didn't confuse you further but I really think JA is still an option to consider, and may cause less stress for you.
Thank you Starrysim. You are 100% right with that, I want to have piece of mind without any hassle.
And what comes to JA, I almost forgot it all. Yes, it is def option.
New ring looks always fresh and nice
Its hard to find the diamond to setting!! Maybe thats the reason why I have looked second hands, cause everything is already made up! For 680$ just wondering how good looking diamond you get with that.
I know im in very low budget to compare other users here, what I have seen like "I have only 15k to spend for a diamond"