I would like to pay out customers in BTC , what are some of the most cost effective solutions out there ?
Option 1 should be LN payments, but I don't expect that be possible in your case.
Obviously at least you should have SegWit address.
And I'd say that you should somehow keep an "
account" for each customer (an entry in the database) with the coins "he has" and only allow them withdraw to their wallet if certain
threshold is met (threshold that depends on the tx fees in that month).
And the withdrawals should also be batched, maybe for once a week, in the week-ends, when the fees are usually lower.