Need help with a Saleen wing measurement

[BrendanMoney]

I have a '91 GT Convertible that I want to order the Cervini's saleen wing for but am in the process of ordering a custom car cover first. Ive already sent them the dimensions but Covercraft needs one last measurement in order to make my cover. They need to know how far the wing sticks out from the edge of trunk lid over the back bumper.
any help is appreciated.