That year is very nice but rains caused molds on bigger flowers too, although I may have enough for years (and still have some from previous years!), I got some very big plants but none was close of 1kg per plant, usually 500g of dry well trimmed flowers is already a lot imo... although I already seen pics of plant which was possibly producing the amount the OP spoke about!
My bigger was 745g from a pretty big Lavender strain plant which was very dense flowers. Years ago...
I cut mines down yesterday... too, Grandaddy Confidential, Black Bomb and a "home" strain, sooner I harvested Medical Mass (meh)and Renaissance, only rest a Papaya, a Granddaddy Confidential and a auto which never turned to be auto... it was called Guillotine, big plant with round big flowers... idk how to call it now but it seems to be a cross between a NYCD and a ruderalis...