This is my first daemons list and I've gone for all Tzeentch units. Any way here it is:
The Blue Scribes. 130
Herald of Tzeentch, Bolt of Tzeentch, Breath of Chaos, Master of Sorcery. 130
Pink Horrors of Tzeentch (18), Bolt of Tzeentch, The Changeling. 321
Pink Horrors of Tzeentch (18), Bolt of Tzeentch. 316
Pink Horrors of Tzeentch (5), Bolt of Tzeentch. 95
Flamers of Tzeentch (5). 175
Your point cost for the Herald is off by 15 points, so Ill assume you put a chariot on him and just forgot to post it. Heralds of Tzeentch are amazing (and cheap) HQs well worth their points.
The poster above gave some very good advice;
-Flamers are best in groups of 3. They make very good suicide bombers with auto wounding and glancing on a 4+, but they also have warpfire if you want to be more conservative with their use.
-Horrors work best in groups of 8-12. Anymore tends to be overkill and less then 8 will just disappear.
-And as for heavy support? You need some. Soul Grinders are amazing with the Phlegm upgrade, and Daemon Princes can be customized any way you need. Taking one heavy support is never a great idea as its easy to be focus fired, but two or three means they either have to split their fire or burn one and still deal with 1-2. (Soul Grinders are amazing machines, immune to 2/3 of Glancing hits and 1/3 of Pen hits.)
A note on Tzeentch Daemon Princes; Master of Sorcery tends to be a waste on them, since as a monstrous creature they already get two attacks and only have two shooty attacks; Daemonic Gaze and Bolt of Tzeentch.