sorry, just do not understand this part.
"All HUC addresses with multiples of 10k at a specified block "
If you have a HUC address with 10000 HUCs you will get X CHI
If you have a HUC address with 12000 HUCs you will get X CHI
If you have a HUC address with 20000 HUCs you will get 2X CHI
a UTXO Snapshot will be taken at a specified block - TBD