[Spinnaker]

You did a nice job to avoid the big buck cost of having to have the window replaced by a shop.
I have purchased items from Sailrite before for the boat and they are a good outfit to deal with.
Instead of using thimbles, you might have tried using what sailmakers use to push needles through thick material. It is called a sailmakers palm. Sailrite carries them also. It makes pushing the needle through hard to sew items a lot easier.
http://www.sailrite.com/Palm-Adjustable-Right-Hand
I know it is too late for you this time, but maybe someone else will see this and know what other options are available for them.

Now all of you know why I chose my user name.