Genius Recipes cookbook: Fresh Ginger Cake: substitute for dark corn syrup? I have light corn syrup and Golden Syrup

I'd use Golden Syrup since the flavor is waaaay better than light corn syrup which has no flavor, just sweetness.

I think what you first propose sounds smart. Let us know how it turns out!

Many thanks to you both! I live in the UK and dark corn syrup is hard to find here (though not impossible - I've found light corn syrup but it's used in more recipes I like than dark so it seemed worth the price for imported food products). Thanks for your help!

I've used dark maple syrup in place of corn syrup and it doesn't noticeably alter texture. Of course, if maple isn't a welcome flavor to you, I would use the golden syrup. While its not a seamless transition, I've used honey in place of corn syrup too without harm to the final product. While all liquid and invert sugars are not equal in content, they don't seem to make THAT much of a difference in dense, moist cakes...aside from flavor, which can be welcome at times.

Some of this is chemistry and some is what you prefer.
Using either light corn syrup or golden syrup instead of the dark corn syrup will retain same texture and slightly alter the taste, same with the change of proportion (more molasses & less other syrup).
I would stay away from the sugars & honey (use them only in an urgent need to make cake & lacking syrup), as they will change both texture and taste.