Okay, so I asked on another forum as well, and one of the moderators there was kind enough to provide the following summary from his favorite notation-wonk book:  (Thank you Mr. Giffen!) 
  
Rests must be notated to indicate clearly the divisions of the bar.  1. Rests of one or more beats may only occur (start) on a beat.  2. Rests in duple or quadruple meters (not just simple meters 4/8, 2/4, 4/4, 2/2, but also compound meters 6/16. 6/8, 6/4, 12/8) must divide to expose the middle of the bar.  In 4/4: |n4 r4 r4 n4|, |n4 r4 r2| or |r2 r4 n4| but not |n4 r2 n4|, |n4 r2.| or |r2. n4|. In 6/8: |r4. r4 n8| (|r4. r8 r8 n8| is okay, too), |n4 r8 r8 n4| or |n8 r8 r8 r4.|.  3. Rests in triple meter must expose all beats (two beat rests can only occur in duple or quadruple meters).  In 3/4: |r4 r4 n4| or |n4 r4 r4| but not |r2 n4| or |n4 r2|. In 9/8: |r4. r4. n4.| or |n4. r4. r4.| but not |r2. n4.| or |n4. r2.|.  4. Dotted or combined rests within a beat, are encouraged (formerly not) to increase legibility.  In 2/4: |r8. n16 r8. n16|. In 9/8: |r4. r4. r4 n8| or |n8 r8 r8 r4. r4.|.  SIMPLE METERS  5. In simple (eg. duple or quadruple 2/4, 2/2/, 4/4) meters, dotted rests are recommended for the beginning of a beat but not at the end of a beat (although they are acceptable at the end).  In 2/2: |r4. n8 n8 r8 r4| encouraged, |r4. n8 n8 r4.| acceptable.  6. The longest allowable dotted rest in simple meters is one level smaller than the beat.  In 4/4: |r2 r4 r8 n8| or |r8. n16 r4 r2| or |r2 r8. n16 r4|.  7. Dotted half (or whole) rests in simple meters are deprecated.  8. Within a beat, double-dotted rests may replace two or more rests, but clarity should take precedence.  In 2/2: |r4.. n16 n16 r4..| is acceptable, but |r4.. n16 n16 r8. r4| (or |r4.. n16 n16 r16 r8 r4|) are probably clearer.  9. In the middle of a beat, rests should exposel the middle of the beat, although this isn't necessary when the rhythm is clear.  In 2/2: |r2 n16 r16 r8 r8. n16| or |r2 n16 r8. r8. n16| but not |r2 n16 r4. n16|. In 2/2: |n8 r4 n8 n8 r4 n8| is acceptable (clear rhythm).  COMPOUND METERS  10. Dotted rests as whole beats are standard. Combining whole beats must not obscure the important divisions within a bar (eg. middle bar in 6/8, 6/4, 12/8).  In 12/8: |r2. r4. n4.| or |n4. r4. n2.|.  11. Within a beat, rests at the beginning of a beat may be combined.  In 6/4: |r2 n4 r2 n4|.  12. When rests occur for more than the first two subdivisions of a beat (but not the entire beat), combine to expose the second subdivision of the beat.  In 6/4: |r4 r4. n8 r2.| but not | r2 r8 n8 r2.|.  13. For rests that follow a beat, all three subdivisions of the beat should be exposed.  In 6/4: |n4 r4 r4 n8 r8 r4 r4|.  14. When rhythmic feel must be communicated for rests at the beginning of a beat, rests should show these (don't combine).  In 6/4: |r4 r4 n4 r4 r4 n4| or |r4 r4 r8 n8 r4 r4 r8 n8|.  15. However, it is better normally, and in long bars especially, to combine rests to make position of beats clear.  In 9/8: |n8 r8 r8 r4 n8 r4 n8| instead of |n8 r8 r8 r8 r8 n8 r8 r8 n8|.  16. In the middle of a beat, expose at least two or the three subdivisions of the beat.  In 6/4: |n8 r8 r4. n8 r2.| or |n8 r8 r4 r8 n8 r2.| but not |n8 r2 n8 n2.|.