Custom server rack desk addon

[Zendrith501]

I want to make my new pc possibly inside a server case (idk what one yet but have an idea, suggestions for that are welcome!). I made a desk a few months ago and want to add rails to the desk to allow a 4U server case to be placed in some free space of my desk. I was wondering what rails i should grab, and mainly how far apart the rails have to be to allow a server case to sit in my desk. the desk has 1/2 inch pipe for the framing and a 63 inch x 25 inch desk top. the area i want to ad rails to is the cubby area just above where the base to my speaker set is 19x19. Im totally fine with making a new desk if i have to; in fact its fun to do it too. or just modifying this one and getting some more pipe to change the dimensions of the cubby area for a server case to fit. sorry if this post was a bit all over the place its basically 1 in the morning for me