Rack spacing question

[Fritz]

Googled this and I'm still confused. I think what I need to know is where does the rail go in relation to the hole spacing? There's 2 ways to look at this as far as I can tell.

1. Where does the rail securing hole go (the hole the screw goes into that holds the server in)
2. Where do the rail securing tabs go in relation to the hole spacing (Supermicro 4u rails)

Also. Should I leave gaps between the servers?

TIA

 

[Churchill]

1. The top and bottom hole have to line up so you can screw both in correctly. If the top and bottom holes do not line up, go up or down depending on your location until they do.

2. No idea on this one.

3. No space between servers unless you have mountains of room with few pieces of equipment or your cooling situation requires systems to be spread out apart.