80 box The LCRA web site has recently added a listing for a gauge on the James River near Mason. I don't have a sense yet of how the measurement of flow at the new gauge correlates with the Llano flow, but because the James is wide, I would suspect that you will need at least 500 cfs on the new gauge to do the run. The LCRA web site also has new gauge listings for Comanche Creek, Willow Creek, and San Fernando Creek near Mason, Hickory Creek near Castell, and the Little Llano River near Llano. Comanche Creek flows through Mason and is west of Willow Creek. Comanche Creek and Willow Creek look like they have the easiest shuttles and access, but all five drainages are smaller than the Beaver Creek drainage.
Local storms can have a big impact.
In October 2000 a gully-washer brought San Fernando Creek up to 600 cfs when the Llano River was still only at 200 cfs. You probably need at least 200 cfs for a run on any of the newly listed creeks. I know of no one who has done them. 71 gauge is now called Sandy Creek near Kingsland. This is really useful if you want to run the premier whitewater creek in the state, Crabapple Creek.