Triumph Repair: fitting a windshield, metal rim, glass companies

Question
I am trying to get a new windshield to fit in my 1980 Spit.  It seems like the thing is too big to fit.  The rubber fits the windshield perfectly, howevre when I get it up to the frame it is about 1/4 to 3/4 inch larger than what I think would be a good tight fit.  Is this normal?
How do you cram one of these thing in?  Is there a special pry tool?  I tried the method of wrapping a cord in the slot around the rubber to facilitate pulling the rubber lip over the metal rim of the frame , but I could not push hard enough to bring the rubber lip close enough to the rim to slip the rubber lip over the rim.

thanks for you help.

Answer
Hi Kieth,
Installing a glass in a windshield is very difficult on some cars and you can even break a glass trying. That is why there are glass companies in business. They are mostly very skilled at doing this. I have installed many windshields in many different cars and almost every time I finish I swear I will never do another. This was hammered home when a friend asked me to do one for him and I was too busy to do it right away so he took it to a car glass company and they put it in in just 30 minutes and charged him about one tenth of what I wanted to do it for. So I take my own to glass companies to do now. However, you need to ask up front what they charge to do it when you are supplying the glass. They don't like to do that because they too sometimes break a windshield trying to install it and if it is your glass they may tell you that they don't want to be liable for it. You may be ok in this case because they may not have a source for a Spitfire glass. Call several to get an idea.
I would not take the job on if you were at my door begging and offering tons of money.
Howard