Sort. You don't need to /window -s auto-sort timestampped echos. C'mon Ouims. That would be silleh!

And yes. /echo works in Custom @windows just fine, Erasimus. You can even use the -m and -l switches to adjust the window and text event/message/highlight color, and the -b and -f switches to support the beep and flash global behaviors, and the -i and -c switches to support default indenting and color stripping settings. And -t for timestamps. All these switches you want to use for emulating Message/Channel Text.
Well. At least I won lunch.
Good philosophy, see good in bad, I like!