Scale Video textures and position into a grid

Questions
1

I’ve improved my example to dynamically add video textures , scale and position into a grid. Sadly I can’t seem to get each video group scaled to a calculated width, and position correct. The widths are calculated by how many columns are to be added. For 2 videos, it should be half the viewport width. Calculating half of the detected viewport width it won’t scale or position properly.

https://jsfiddle.net/danrossi303/86huq0fn/4/