So while this resolves, what client is best if you need to send some coins to an exchange?
Do you mean
before the split?
Because every transaction that you make before the chain split will be mirrored to the other blockchain, so there's nothing to replay in that case.
In other words: You already spent your coins so you don't get forked coins.
Or
You mean a precaution against replay protection
after the split?
If so, you'll need to have both clients and enable "
coin-control" to be able to create a transaction in the "
Altcoin blockchain" that spends the forked UTXO back to your own wallet's address.
That way, even if someone replayed it in the Bitcoin blockchain, you're still the receiver.
(
if it's replayed, don't proceed to the next step)
Then after it's confirmed, proceed to spend the Bitcoin UTXO to your intended exchange.
Its forked UTXO in the Altcoin chain is already spent so the transaction can't be replayed there.
Coin-control is a hard requirement for this to spend the correct UTXO, unless you have a single UTXO in your wallet.