How often are sidechains expected to update the mainchain?
The two factors involved seem to be:
Shorter wait - more txs for the operator to put through on mainnet (more costly).
Longer wait - the longer the recipient has to wait to be certain he has received the funds.
I realise there’s no correct answer to this and likely depends on how many txs are being made on the sidechain per second, as well as fees the operator is charging, but still interested to hear what the plans are for initial plasma operators.