Thanks guys! dinohunterpoa, I thought about using a wash or something, but having tried that on some Reaper 'see-through' minis, the results were discouraging. Although like I said the material Reaper used was inferior to this in my opinion. might work better on these, but I decided to leave them as is.
I guess you're right midismirnoff, technically they're blink-dogs or something, but it said hellhounds on the label I think? There was a picture of these painted in black and red on the reverse side of the blister, so that would be more like hellish dogs. But then you wonder what's the point of casting them transparent? I'll just use them as is, nice and quick.