Daikon minowase, when to harvest

Online i have seen videos but they are harvesting gigantic daikon that are popping out of the ground.

Mine have flowered so i thought I should harvest them, but pulling one up it was tiny.  Do they develop after they flower or do they just not work here??

Most of mine were the same way, but I have grown them large in the past.  Not sure what went wrong this time, maybe planting too late?

I have found that planting them in the spring here, doesn't work. They bolt, flower and try to set seed before I blink. If I plant them 60 - 70 days before first frost date, they get to a usable size. I've seen a field of them in October, white columnar roots sticking up out of the ground. Bigger than mine get.

Other roots get inedible when they flower. It's like chewing spongy wood. Ugh.