I'd like to build an elevator for my apartment building. My plan is to use [rails](https://www.bricklink.com/v2/catalog/catalogitem.page?P=4510&name=Plate,%20Modified%201%20x%208%20with%20Door%20Rail&category=%5BPlate,%20Modified%5D#T=S&O=%7B%22st%22:%224%22,%22ss%22:%22US%22,%22rpp%22:%22100%22,%22iconly%22:0%7D) and [grooves](https://www.bricklink.com/v2/catalog/catalogitem.page?id=90291#T=S&O=%7B%22st%22:%224%22,%22ss%22:%22US%22,%22rpp%22:%22100%22,%22iconly%22:0%7D)  to allow the elevator to slide up and down. This means I have to build the elevator with the studs facing forward instead of up. I'd like to have 4 rails on each corner of the elevator and slide them along grooves outside the elevator.  

Here's some pictures of what I've built so far:

[![Elevator car (click to enlarge)](https://i.stack.imgur.com/BPrAI.png)](https://drive.google.com/file/d/1Q_C4B92uXlQH6ZOQY5t1RID_pdCd38kV/view?usp=sharing)  

[![Alignment problem (click to enlarge)](https://i.stack.imgur.com/PJu3E.png)](https://drive.google.com/file/d/14qIQhUuegT-nc3ze3LjnokDZi4M7zxDL/view?usp=sharing)

The problem is that because of the dimensions, I can't quite get the grooves and rails to line up with eachother. How do I calculate a set of dimensions for the elevator that will allow it to attach to 2 pairs of grooves. I supposed I could use just 1 pair of grooves in the middle, but I think that would be less stable.