To be honest, generally if I am bonding rescue bunnies, if they don't get along, we would try another rabbit where they do want to get along and the relationship isn't forced. Like humans some buns actually want to get along and I've had washy head almost immediately. With some it's taken a few days and the relationship does grow. My concern - having seen it, is that if the two rabbits don't get along wonderfully but tolerate each other, the relationship may not be the best one for the rabbits involved.
Now with rabbits that already belong to the person and I'm just helping to get them together, I have gone down the road of trying several times over a period of months.
Ultimately in most of the cases the rabbits just don't like each other or aren't suited. One pairing, recently, we tried twice and that was even after the rabbits living next to each other at home. So we ended up bonding a different rabbit to one of the ladies, and the other one is going to be rehomed so she can go on to live with a partner that she does like.
Every case is different, but if you have to try everything to get your own, already owned rabbits together then I'd say yes, try it again, and if it fails, try side by side living and progress to the full on introduction.
With a pair of my own rabbits I have tried side by side and failed miserably but have on two occasions tried instant intros, and where it didn't work the first time, done it again in a few days and it's worked well.