Quang is correct that Sweetheart is one of the earliest varieties but Sweet Cliff and Groff can be earlier but it depends on your microclimate.
Kaimana has a unique fruit shape that is large and often wider than it is tall. It looks short and wide is what I’m trying to say. It also has this vertical line that other varieties also have but is very obvious in this variety. It also has a small seed.
For cross pollination, you want a consistent bloomer year in and year out, Brewster, Mauritius and Emperor are all consistent bloomers here because cold weather is the main stimulus for floral induction.
I’ve tried overwatering my trees during fall/winter dormancy to prevent blooms and it didn’t work for me. High levels of nitrogen pre bloom also didn’t work for me. If you want more blooms however, a dry period pre bloom is highly recommended.
The secret to Lychees vegetative growth is ample amounts of Iron along with your basic orchard fertilizer regimen.
The secret to( nutrition wise) to better blooms and fruit set is a good quality cold pressed seaweed/kelp emulsion pre bloom and and throughout fruit sizing up. Yeast supplements may also be beneficial for fruit retention as is girding or cincturing but this is a technique best left to experts unless you are not afraid to lose the branch.
I also don’t want to scare anyone away from trying girdling however. If you’ve been successful at air layering a Lychee or Longan, you can probably reap the benefits of girdling.
Simon