DIY Rackmount Case question!

[austinm08]

My width came out to be slightly too wide, so I narrowed it a bit and I am wondering if it's okay if the distance between the two rails (not the holes, but inside edges of the rails) is 17 and 5/8" rather than 17 and 3/4" like this diagram depicts:

 

[moresound]

Should be OK as long as the units will fit in the space. there always seems to be a little play on that measurement.....but I would double check all of your gear first to see that they fit.