Now I'm trying to use Electrum to store my BTC with the cold storage way.
But there are still some questions which confuse me, could someone give me hints about that ? I searched the forum and haven't found what I want.

There are two wallets and one is offline electrum wallet(W1) and the other is a online one(W2) which is generated by the master-pub key from the offline wallet. Both of them have the same addresses.
After lots of transactions are done, as I learned from electrum documents, there would be new addresses generated by W1.
The questions are:
     1. Could W2(watch-only wallet) show the correct balance info for this address ? If Yes, How does W2 know this address is generated by W1?
     2. Is it enough to restore all the balances and info from the seed without the wallet backup file after new addresses are generated? If Yes, the only one I  need care about is the wallet even after lots of transaction are done, that would be awesome.
     3. Does the change_gap_limit have bad effects of the cold storage or wallet restore?


Thanks for helping a newbie,

ora.zhang