Hey Flashing,
No one in there right mind would restore their foreskin to make their penis look bigger, but yes, there is a size advantage. It would seem to be a small advantage. On the one hand, it has been said that you might gain up to 1/4” (~6mm) in length per year. I am in the process of restoring and I definitely have gained a small amount so far. But when you have restored most of the way, your woman will start loving it. Sexually experienced women who know the difference can FEEL the foreskin bunching up at the opening of their vagina and they definitely like it. They know the difference and it does feel somewhat bigger. There is more there and they can feel it.
But I may have misinterpreted your concern here. Just let me say that the reasons for restoring are of a much different nature than the desire to get a bigger penis. If you are circumcised at birth and are now still a young man it is very difficult to understand what it will feel like to have a poorly functioning sexual organ when you are older. In fact, many men don’t even understand that their sexual performance, regardless of their age, is greatly affected by their circumcisions at birth (adult circumcision is a much different thing).
Restoring your foreskin will completely change your sex life for the better. I am very confident saying that. Just make sure you understand that restoring and penis enlargement are two different things.
I will try to check in soon to respond to other questions you may have.