One question on this though in regards to Android. How/can one switch between wallets on Android? I looked but see no such option.
The current Android version is deprecated since 1.8.3... meaning that it will no longer be updated. (you can try compiling it using 1.9.8, but it will be super buggy)
2.0 will have a newer Android version that will come out on the Android Google Play Store and the UI will be 100x better.
However, with 1.8.3 Android (the crappy one) the way you do this is as follows:
1. You create your main wallet. Then exit Electrum.
2. You use a file explorer app to go into the sd card and change the name of wallet.dat to wallet.dat.old or something else.
3. Open Electrum again and it will ask to create a new wallet.
4. Click restore. Then click QR code. Then scan the QR code of the Master Public Key from your wallet you want to watch.
5. Now to switch between wallets, just make sure the one you want to open is named "wallet.dat" It might help to name the one that is not wallet.dat whatever it is... so if you see "wallet.dat.watch" you know the main wallet is wallet.dat and "wallet.dat.main" would let you know the watch only wallet is wallet.dat... etc.
Android for 2.0 will have multiple wallet access from the main menu screen, as well as access to multi-sig that can work together with your PC etc. for 2FA