14k rose gold soldering struggle - advice needed!

Hello all!
I have been silversmithing (usually only silver, sometimes copper and brass) for a couple years but was recently commissioned to make a simple wedding band in 14k rose gold (with 7.8k rose gold solder).
I'm having a lot of trouble with the join (on a plain band!! ridiculous, I know!) and it's really making me question my skill (or lack thereof?!).
It's my first time using gold in any form, so I'm positive there are things I need to know that I didn't find in my research prior to commencing the job.
It's quite a thick band at 1.5mm (5.5mm width) which I believe is not helping the matter, it's been increasingly hard to get two flush sides for the perfect join (any tips for this also welcome!!).
I am welcoming any tips, tricks and advice, as I'm beginning to worry a bit! I don't want to ruin this piece of gold as I can't face a disappointed customer or the hundreds of dollars I'll lose.
I need a win!! Please help!!

Thanks in advance,
I solder both 14k rose and 18k rose with stuller pink solder either easy or hard. the trick is to have a nice fit, you can make it real tight by running a saw blade thru the cut. then i coat with boric acid and alcohol solution to keep the fire scale down, lastly I use some batterns flux to help keep the joint clean while heating. the trouble with rose gold is the copper that makes it red, you need to keep the joint free of cupric oxide as it will prevent the solder from flowing. with the hard solder you need to be careful not to melt your piece before the solder flows. I find it is much like hard soldering silver. you need to heat the whole piece or at least keep the sides of the shank pretty hot so that the heat is not taken from the joint and spread across the whole piece, copper like silver conducts heat very well. the other thing you should know about red golds are that they work harden very quickly, anneal often. I hope this helps and would like to see others comments about working with rose gold.
Struggling with soldering metal together using a 14k rose gold joint clip, I recommend seeking help from an experienced jeweler. There could be many reasons this is happening, and it may be more complex than just needing to use a different solder. In some cases, the joint clip might not fit well, or something could be wrong with the connections between the clips. A jeweler will know more about how to fix these issues and get your jewelry back up and running smoothly.