...will be launched on the 1st of August. Are you happy with this?
Bitcoin doubler isn't such a good word, maybe use a more technical term. It is pretty hard to predict what will happen in the future but this definitely seems possible and the prospect of this happening isn't that unlikely.
What is the best way to prepare for two chains? If I transfer BTC to a core desktop wallet before 8/1, How do I make sure I can spend them on both chains? Will there be a different wallet program compatible with the core wallet.dat?
Well in preparation for August the first, the one thing you must have access to your private keys so I would definitely recommend a buying a ledger wallet or trezor wallet so you will have access to your private keys, which gives you certainly that you won't lose your bitcoin through a hard fork, which is what segwit is. There is