How to align a grid evenly spaced

I’m not sure if I’m using the correct terminology here, so bare with me please. Basically, I want to create a grid on a piece of marker board that I got from the home center. My problem is that each of the negative spaces between the lines seem to be just a mm or 2 off of each other. Is there a way to select all the vertical pieces, for example, and snap them to a standard distance from each other?

Thanks.

Easy in Inkscape, not possible in Easel currently.

If I did it in inkscape, it would then scale to whatever size I changed it to in easel, correct?

Sure.