70 convertible top

I have a 70 barracuda with a Haartz convertible top with rear glass. Can anyone with a similar top give me the dimensions of the rear glass in the top. My problem is that the top will not open all the way as the glass hits the trunk hinges and will not allow the top to go all the way down. A professional shop installed the top which they ordered and installed. My thinking is that maybe the glass is the wrong size.