Unfortunately as far as I can see there is no option to set manual fee when using option Transfer All to My Wallet or to my address.Maybe I miss something because I use blockchain wallet for the first time.Any suggestion/advice is welcome.
Why don't you just sweep the keys directly from your blockchain.info wallet to your other wallet? You don't need to go into transferring the bitcoins first into your main blockchain.info wallet, and then sending it to your other wallet. That step is redundant and will mean you lose money on fees.
If you want to set a manual fee, then simply go to send, and selected the imported address that you want to send bitcoins from. AFAIK you cannot combine inputs on blockchain.info with imported wallets, so you'll have to do this one address at a time. Go to advanced send, and set your own fee. But by not following blockchain.info's recommended fee you are risking your bitcoins not getting confirmed in time.
I use MultiBit Classic and it stop working so I try to import private keys in Electrum,but some of addresses have to many inputs so Electrum just stop responding.In case of sweep keys in Electrum I need to pay fee to transfer BTC to one address generated by Electrum,maybe I should try that but I use blockchain wallet&Electrum import pk and I transfer BTC to my new wallet.Some addresses have small inputs so I use Electrum to send coins,other problematic with too many inputs are handled by blockchain wallet.
Anyway I am satisfied that my coins are safe and that in total I pay very low fee for my transaction with little help from ViaBTC.