In regards to zygotic seedlings, C-35 is approximately 15% zygotic. Carrizo and Troyer can be as low as 1-2 % zygotic. I have no experience with Carrizo - Troyer cold hardiness. C-35 performs best in uniformly cool winters (within limits). C-35 does not fare as well in areas prone to sudden freezes following warm periods during winter. The references I've seen consider the three to be similar in cold hardiness.