Cisco Switches :: Dual SG 300-10 Mounting And Cascading?

SG 300-10 user manual states to not mount the switch on either side (I'm assuming this means the right or left ends as you face the front) and that they can be mounted either face-up or face down or flat). The specs further say that a 5" space must be "around all sides" of the unit. Silly question is what does "all sides of the unit' really mean? (of course given you must mount is somewhere). Also, given the little feet supplied with the unit, it is implicit to me the bottom needs to be only about 1/32" from the horizontal surface it is placed on. If this is true, can this unit be mounted face down on a shelf such as the Leviton 47612-UBK (it's allowing the mounted units to have airflow between the unit and the cabinet back) and have a second SG 300-10 mounted in front of the first that is seperated from the first by either the dual feet or use separation spacers that will fill the available shelf space and maximize the distance between the units - all without degrading the inherent reliability of either?
 
Lastly, The two SG 300-10's are reaching the internet through a LINKSYS E4200 router. Is it better to have each SG 300-10 occupying its own dedicated port on the router OR to cascade one SG 300-10 to the other SG 300-10 then one of the LINKSYS E4200 router? If the answer is each occupying their own dedicated LINKSYS port, then would it be prudent to load one SG 300-10 with the most active ethernet lines to allow the other SG 300's port power management to shut it down?