Selecting all intensity channels in a cue

Depends if you are on an Eos or an Ion. On the Eos, there is a button [Select Active] - this will select all channels above 0.

On the Ion, you hold down [Select Last], and {Select Active} will be a softkey.

To bring things down 10%:

[Select Active][At][-][1][0][Enter] will take everything down 10 percentage points.

[Select Active][At][/][9][0][Enter] will scale everything to 90% of its current value.

-luke-

Another option is [Group] [Cue] [Enter] (or [Group] [Cue] [x] [Enter] for a non-active cue) which will work on either console.  You can then use the same commands that Luke mentioned for bring the intensitys down.