Thanks, yeah I've put a few days into this topic & it still needs work. You're right that I skipped over discussing accounts, it's not entirely clear in the docs whether or not you can sharedrop without creating an account for the recipient.

Looking at the BTSX->BTS snapshot, both the initial_balances & sharedrop_balances fields reference the BTSX key not a BTS account, and searching cryptofresh for the account yields nothing. However, this genesis file did create initial accounts so perhaps an account per planned balance sharedrop is required?

Both BTSX and PTS-DPOS created sharedrops against Protoshares which is a smaller version of what would need performed against the BTC network. They both reference raw addresses without pre-registering accounts for these balances.

What would be best is if we could specify an 'uia_balance' for each address, and allow the user to import their BTC private keys into an existing Bitshares account, so we could avoid registering 52 million bitshares accounts (very expensive for the sharedropper).

I'd greatly appreciate any developer input on this topic, some of this is pretty complex and undocumented.