Certainly you can install your lighting closer than necessary or further then recommended. There are a few 'keys' to getting the right fixture.
Of course, the first is that it's the proper type of lighting for the intended purpose. Then, it needs to LOOK 'nice'. Then, you need the right amount of light, whether you use few fixtures BUT lots of wattage (in each fixture), or a lot of fixtures with LESS wattage (in the fixture.) THEN, there's the bigger picture of how much electricity you'll use. I've seen homes where there are ALL kinds of lights on on as many as 4 floors where there are rooms with no one in them. (It's a personal peev w/me when it comes to lights on in rooms w/no one in them.) Don't confuse my 'peev' with leaving a low-wattage light on in a room with no one in it. WHat I'm talking about is rooms with 150+ watts on w/no one in them! Well, that's another story ...
The height of the lighting will affect the aforementioned 'criteria' too. So, there are a few variable you need to address. Yes, there are coverage ratings from the MFGR of the fixture. Just be SURE to get the type of bulb AND its wattage when they provide you the info. AND the height of the fixture should be provided too. Contact them for that info.
My best to ya and hope this helps.
Jay J -Moderator
PS: If I didn't imply this, you can break whatever 'rules' you want by adding more or less lighting at whatever height with whatever wattage. I know there are professional Lighting Designers who know all about this. Visit My Favorite WEB Search Engine and start clicking! Maybe you'll find a 'tool' that can help with planning you Layout.