The normal looking offspring of the recessive double het pair would have a separate 2/3 chance of being het for each parent type. The cumulative chance of being het for both would be 4/9, so pretty close to 50% but not quite. I think such babies are under rated because they also only have a 1/9 chance of being completely normal. I picked up a male 4/9 chance double het for VPI snow pretty cheep years ago and the females weren’t all that much more. Lots of people don't like possible hets and miss out on stuff like that.