High rise beds

Dad recently gave me a bed frame that belong to my grandfather. The frame is a full size so it required new mattress set since I only had queen sized sets. So away I went to get a new set to fit the frame. Few days later I have the new mattress and box spring in the house and everything ready to be set up. I put the bed together and discovered how ridiculously high it sits. You can barely set the head board.

Obviously new mattresses are not made to be used with the old wooden frames that is made hundred years ago. I don't have many options with fixing this other than returning the box spring for something extremely thin or modifying the frame. The side rails have a ledge on the inside for slats to sit that actually support the mattress. If I remove this ledge the mattress can sit lower than the bed frame on a modern metal frame. So I can have the keep the decorative frame and drop it down five inches to a more reasonable height. This will also make it where the weight isn't supported by the antique frame, reducing the risk of damage.