Harness for hard to fit chihuahua/jack Russel terrier mix

I've bought two different brands of the same kind of harness (the second being the Ruffwear Front Range), and neither of them worked, making me realize that the problem is the shape of that type of harness. My dog's chest measurement is 16" and that shape harness just rubs up against her poor little neck, creating a gap in the bottom fabric that I'm afraid could catch on something somehow if she was running around outside with it. Overall, it's just not comfortable. I wouldn't consider her a super long dog, or her neck super short, but that's how this thing's fitting her.

Does anyone have a recommendation for a harness that attaches to the leash at both the back and the front, and won't rub up against her neck? I'd really like to figure out a harness that helps her learn not to pull as much but has flexibility in the attachment points. I have a cheap-o harness (same shape as the Ruffwear Front Range but less nice padded material) that I'm trying to use in the meanwhile, but again, it all bunches up around her neck when she backs up due to its poor fit, and is overall not as comfortable looking as a preferred longterm harness.