Rappelling with small diameter ropes

Hi, I’ve been getting into scrambling more in the boulder, CO flatirons and I’m trying to figure out a setup for rappelling off a couple of the formations that I don’t feel comfortable down climbing. I’m trying to keep everything as light as possible so I can still run the trails and not be weighed down, while still maintaining a high level of control on the rappels. I’ve only used 9-10mm ropes before so I’m just not experienced with the friction and use of the smaller ropes. I’m looking into a 8mm rope using an ATC w/ a prusick, but was wondering if I could go smaller. Say 7mm with atc and prusick, use a tag line, or a different rappel device? Thanks 

If using a rope under 9mm it would be best to use a device made for ropes that small. BD makes an alpine atc made for smaller diameter ropes. 

when i am rapping on skinny lines i like to add another biner to the atc. really helps clamp down on the rope better.

Two ideas:

- extend your belay device and use your ATC. Then using a biner off your leg loop clip rope using a Munter hitch; two systems now adding friction/control.

- another technique, Z rappel - again extend your ATC and rig for regular rappel. Run rope down to leg loop, clip rope through a biner, and run rope back to ATC. Clip a biner to the ATC biner and run rope through this biner. This configuration forms a “Z” shape to the running rope with 2 bends increasing friction.