HELP! Substitution for corn syrup?

No one really answered my question the last time I posted this.

Okay so I want to make Marshmallows in the future, and the recipe calls for 2/3 cup of corn syrup the lite kind.

Now they say Agave is like 25% sweeter and so you use less. Now I figure that I might use half a cup instead?

Also Honey is also a choice I have. Now I've read many times that I could use and equal cup of Honey to replace an equal cup of corn syrup.

Now since the recipe calls for the above 2/3 cup of corn syrup then would I be able to use the equal of honey?

I know this is silly but this is driving me nuts cause I really don't want to have to use corn syrup, not even the organic kind, cause I just don't like that it's in everything!

I've also found flavored Agave syrups too. Two I really like are the Chocagave and Vanillagave syrups that would most likely taste really good. They are called dessert syrups but then again I've heard Agave can be used as pancake syrup so I'm guessing there isn't much of a difference other then sweetness.