Arming and moving DH Stormtroopers?

Being new to Daemonhunters i have a couple of questions about ISTs.
1) How to arm the squad and sarg?
2) What squad sizes work well?
3) How should they be transported?
4) What are the main roles of ISTs in a Grey Knight heavy force?

Thanks in advance

Don't bother with the Sarge unless your giving him a melta or plasma gun. 8-10 models for the IST with either two melta or two plasma guns in each squad. Preferably give them pimped out Chimeras if you have the points. They can be used as objective holders to free up your GK's to do other dirty work. If you do have Chimeras/Rhinos for them they make good moblie tank hunters.

Which is better for them, Chimeras or Rhinos?

for IST : chimera but a little more expensive in points
Aubec

Why do you say that?

Chimera's are more expensive to buy as a dedicated transport for the ISTs and Inquisitors, but I'd have to say that its fire power is much better then that of the Rhino, along with its front armor value of 12 compared to the Rhino's 11. But the Rhino makes up for this with its side values at 11 compared to the Chimera's own 10.

If you want mobility with ISTs, then a Rhino would help a bit since a base squad upgraded with a rhino is about 100 points.

+1 with DarkRonin plus you can transport 12 guys in a chimera than can fire too !
Aubec

I just have the feeling that a Chimera would look out of place with the GKs, Dreads and Landraiders

They'll only look out of place if you don't have any storm troopers for them to ride shotgun in. The Chimera/Rhino would provide extra protection for the ISTs as they roam about the field capturing points or tank hunting with melta and plasma guns.

Im going to use the Kasrkin models, and in Inq colours they fit in well with the GKs. A different style vehicle could stand out abit too much

if i remember well in the Imperial Armour 7 (siege of Vraaks III) you have examples of chimera with inquisition colour-code and they look quite good
Aubec

My other half has just got that book sp ill take alook

major point:

both of your special weapons can fire from a chimera. Only one can fire from a rhino.

also you can usually keep the army shooting at front armor if you have two tanks, so chimeras usually live a little longer.

That is a good point. I like to have a very functional force thats as strong as possible. But with only 1 limitation.
I dont like using models that Im not keen on building and painting as soon as I see them.
And the Chimera is putting me off more and more each time I see it