Kandra blessings probably have something to do with where you spike the victim, in order to tear off the correct bit of soul. Koloss might be a result of spiking the wrong/a different bindpoint in their creation, resulting in side effects of loss of intelligence and blue skin and so on. Kandra Blessings of Potency could be the result of tearing off an extra bit that acts as a key to the kandra spiritweb, completing it.
Hemalurgy requires great working knowledge of the bindpoints, and I think this is important in both the initial spiking and the final.
Counterpoint: Wax's earring was an inquisitor spike and worked just fine on Paalm, so maybe no special construction is stricty necessary. Kandra are weird with spikes, anywhere seems to be a valid bindpoint.
