So after reading Invocation of Nehek carefully (as I was considering taking Blood Knights in my army for the first time) I realised that it doesn't limit the amount of wounds that a unit of vampiric/ethereal/large target's would get, only the individual models. Read carefully - 'However, models with the Vampiric, Ethereal or Large Target special rules can never regain more than 1 Wound per successful casting.' The word used is models and not units, does this mean each individual model can gain 1 wound? if so, this would apply to hexwraiths too... so in fact they would gain 1 + wizard level?
Is this correct?