Re: Any TF beekeepers from Sacramento area?
This is a limitation of the hive you are using as much as it is of the genetics.
Italian genetics tend to overwinter with large colonies. Unfortunately, they also tend to be very susceptible to varroa. My experience with mite resistant genetics is that they almost always overwinter with small healthy colonies.
Frame spacing is the other piece of this puzzle. A small cluster of bees can cover roughly 30% more comb space if the combs are spaced 32 mm center to center vs Langstroth frames that are 35 mm or Dadant frames that are 38 mm. With plenty of stores, a small cluster, and a good queen, bees require about 8 weeks to build up to full strength. The negative is that a colony that peaks before the main flow starts will almost always swarm.
NW Alabama, 50 years, 20 colonies and growing, sideliner, treatment free since 2005, 14 frame square Dadant broodnest