what a wonderful present!
Did you find the reason or are you still looking?
I also own a David 3.
And had a lot of learning to do how to adjust things to make it work perfectly.
I had great assistence from Louet. Together we lokated the problem an found a solution. Don't hesitate to ask Louet.
I would realky like to help you, but I am a bit confused what causes your problem.
My sheds are always 2 - 2.5 inches wide.
Some ideas :
Could be the knurled nuts catch up on one another, or one of the tieup cords is wrong attached, or it's a problem with the springs, if they have different tension.
But every things solvable! Don't give up!