Vintique Rallye Wheels

Alright. This isn't rocket science but I'm trying to get this right the first time. I've got 1" between my tire and the leaf spring and 2" between the tire and the wheel opening. I measured my stock 5.5" wheels and they have a backspacing of 3.75".
The 7" Vintiques have a backspacing of 4.25".
The way I figure it, the wheel will move .5" closer to the spring and 1" closer to the wheel opening.
Did I calculate that correctly?
Is that enough room to allow for suspension travel and sidewall flex?