hard top window seals

Hi

I have been changing the window seals in my series 3 hard top side Windows as the filler keeps dropping out. I went to paddocks last week and picked up 2 sets to do both Windows I removed the old seal and cleaned the window etc. But then started to refute and it's about 12'' short, is there different sized windows in the hard top backs between series 1 2 and 3????

Any suggestion would be great and what is best way to refit the window???

Cheers steve