I have tried this and it indeed works. However, the swap is reset upon reboot and I would have to manually open the app and press the "External > Internal" button.
This is not a major problem, but I find that my sdcard1 has files copied from sdcard0. Using ES File Explorer, I have found that the swap copies folders such as Android, data, Download and WhatsApp etc from sdcard0 to sdcard1.
Interestingly, all these folders are empty, which is great, otherwise this trick would be rendered as redundant.
Just wondering if this phenomenon is normal?