Fe 450 2005 Overheated - Reassurance Sought!

it's prolly ok, but you obviously ran it too long.
fill it to the proper level, run it til reasonably warm, let it cool, check liquid level, add if necessary (not to the top, but a few mm above the fins).

You should be OK as Ned stated.
You don not want to run these bikes longer than 2-3 minutes tops at idle on initial start up. No longer than 60 seconds at idle once warm. When you refill the radiator, only fill it to about 10mm over the top of the core. You need to leave room for the coolant to expand.

For some reason, even without a fan, my 650 has never boiled over or overheated. I've ridden in 95 degrees, both slow trail riding, and on the street waiting in traffic lights for at least 2 minutes at times. It gets hot, but not real hot. I rarely shut it down at lights, unless I'm waiting twice.

I'm using some reddish orange auto coolant. Don't know what brand it is. I use 30% coolant and 70% distilled water with a few capfuls of water wetter.

Water wetter helps adhesion and flow. Water, with water wetter in it dribbles down the side if you pour it out of a cup. Much more so than straight water. It's good stuff.

Water is a much better conductor of heat than coolant.You really only need enough coolant to lubricate and keep it from freezing. I think a 30/70 mix protects down to around 15 degrees if I'm not mistaken.