Kommissar Kel wrote:Quick add-on: You cannot have a 10 man grey hunter squad + Wolf Guard in a Rhino, it is 11 men. Therefore you cannot take 10 grey hunters for the free extra Special weapon then place a Wolf guard with them and hope to zip around the field with 2x melta + Ld9.

Lastly On when wolfguard are purchased and when they are attached:

Wolfguard are purchased at army creation, in their own unit, under their own unit's rules. They are not attached to the other units until just before before deployment. this means that they will never count as an additional member of any squad you intend to attach them to during army creation(they cannot be the 10 Grey hunter, you need 10 actual grey hunters), but since they are attached before even deployment, they are fully and wholly members of their new squads in game, they can never be picked out(barring special rules, vindicare), and will still count as scoring(when attached to a troops unit) even if they are the only members of that unit left alive.