Walls and Ceilings - Using resilient channels for soundproofing?

I am in the process of finishing my basement and I am interested in decreasing sound transmission from upstairs into a room that will be an office.

I've been reading about how to do this, so I thought I would put R19 or R30 between the ceiling joists, insulate the round HVAC duct leading into the room, and use resilient channels.

My question is regarding the use of the channels. I assume they run perpendicular to the joists. But, how often should they be spaced on a ceiling? Are the same channels used for 5/8" and 1/2" sheetrock? Also, should I expect my ceiling to droop over time because of flex in the channels, or are they rigid enough where that won't be a problem?

Lastly, I have recessed cans in the ceiling attached to the bottom of the joists, so there will be more distance between the bottom of the can and the bottom of the sheetrock if I use the channels. Will that be a problem?

Thanks

The can lites attached to the joists will tranfer vibration.
Attach the channel at 16"oc.
Also, drywall suppliers,(not the big boxes) sell a self adhesive foam tape that when attached to the channel will aid in the suppression of vibration transmission.

The cans may be adjustable (up and down) to accomidate the channel. They are so lightweight, I wouldn't worry too much about vibration transmission. Airtight seals on the lights will also help.