I think the rods can be either...I'd probably choose the one that looked best with the fabric.

Honestly? If it is in your budget...I'd go custom. I have never seen ready-made curtains that didn't look a tad skimpy.

I have never gone custom but I always buy twice to three times the window width and the curtains do not look "skimpy" at all. For instance...on a double window, I have four sheer panels.

If you are doing rod pocket, clip ring or grommet panels and they are standard lengths, buying additional panels works pretty well to add fullness.

I like my rods to make sense with my curtains more than with the other hardware in the room. If they show, I tend to go with wood.

Yes, at least double the thickness and ready mades can look good if they are close to what you need. But if they are off by a lot, then you may need to do custom. However, for me the ready made/custom decision is a function of if I can get what I want in ready made...typically, I can't. That's why I made all of mine...of course, being able to sew makes that decision a little different.