I'd do a three stone using the three you have.
They give a good coverage of the finger, if you line the idea of an eternity.
Especially given the size of your stones, it'd be similar to that of an eternity, and a lot of buyers find them very versatile.
That way you would also only have to pay for metal and work.
I say three stone because I'm really not sure how you'd use your oval stone in an eternity.
A) Your jeweller would have to match your stone all around. Therefore they'll have to source 7 or so more (depending on the spread you'd like) 1.6ish carat, D-F colour, VS clarity oval diamonds.
That's quite a task. It would be a long process for them and costly for you.
B) Your stone is very big to be replicated around an eternity. The largest I've known so far has had each stone 0.5ct, and that sold for £20,000, to give you some perspective. An eternity with 1.6ct stones would look quite bizarre.
C) How would you lay the ovals? End to end or vertically?
You could use all three and do oval, round, oval round I suppose.
But still, I honestly think judging by the size of them, you'd only need the three of them in a ring and you've covered half your finger.
Any further than halfway / two thirds is rarely worth doing because the ring is then difficult or sometimes impossible to resize.
I'd do three stone.
Setting - whatever you wish! I'm sure your jeweller will have some stock settings, or help you decide on something bespoke. Google images are handy for that.
Enjoy!