I have purchased MGB glass from many different sources. Moss, Victoria British, and others. I have only purchased three of the PPG "modified" units, back in 2014 and do not remember them fitting any better than the other 30 that I bought from other manufacturers. I think I just have a different idea about spending that much money on something that can break just as easily as the one costing 1/3 less on installation. If the installation is done carefully and thoughtfully with all the prep work that is normally needed to do these things the cheaper ones go in the same as the expensive ones.
We have more problems with improperly made new corner brackets and other issues than with the glass. Sometimes the rubber glass seal is made wrong and we have to order one from a different supplier. I have even gotten bottom body seals that were uninstallable and had to be returned for an alternative source. The one thing that I learned is to install the bottom body seal into the lower section before assembling the windshield. You just leave the corners loose until you install the bracket screws, but then you only have to tuck in those corners instead of struggling with the whole length.
The length of the screws used is critical. Each and every hole depth is measured during assembly and the screw for that hole is modified in length if needed. Just barely grazing the glass with a screw too long will break it instantly.
This is a silly, long and hard job. We spend a minimum of 8 hours labor on most of these, including the removal and reinstallation of the assembly to the car. More if we have to drill out rusted screws, and recondition corner brackets. This is why you usually will not get a modern windshield repair business to do one of these, and if you try to get an insurance company to cover the bill for doing this, you will get push-back.
Glenn Lenhard
Glenn's MG Repair
St. Petersburg, Floirda
Ph.:727 521-9890
www.GlennsMG.com