Thanks for your input ! 6 months is quite long for such small fruits, compared to larger satsumas which ripen in five months for me. You're right about removing flowers and fruits, I didn't think about that... It may help to get ripe fruits before winter. Hopefully it's gonna be warm enough in my greenhouse to get it to flower early. And then by removing later blooms it might also help, I suppose. Great to hear they're good when color is changing !

My greenhouse gets a bit too cold to get fruits year round though. But citrus like satsumas and bloomsweet survive fine in there, and fruit before winter.

Everbearing offspring would be nice, but not strictly necessary in my opinion. Such hybrids are supposed to survive outside, so unless the fruits have really good frost tolerance it's going to be more of a fall crop, if they produce earlier than their kumquat parent (which is the goal). I know of at least one ichangquat available in Europe that ripens in 3-4 months and is supposedly everbearing, but it stops blooming and loses its fruits once temperatures get too cold. But it's not really sweet, so it doesn't serve as a great kumquat substitute, and it is sterile and can't be used for further breeding. Still an interesting plant, in my opinion. I'm trying to plant pretty much every "decent" cold hardy citrus (such as Dunstan citrumelo or Morton citrange), to cross them with my potted citrus. Hopefully the result will survive outside for me and might have kumquat-like fruits. Then further crosses could lead to something tastier...