So, following to my Lilo Dark update, I decided to also create the iOS 10.3 Beta 2 Setup.App Patch for iPhone 6S and possibly, but not tested, for iPhone 6S Plus. The Setup.App uses a new optimized form so that it fixes the "No more free space" error on TransMAC.
The CFW iCloud Bypass method relies on a weakness on ASR, trying multiple times might get the ASR corrupted and pass the firmware without checking it's structure. This happens randomly, so unfortunately takes different amount of requests from device to device. I don't recommend trying on 64 GB or 128 GB devices, it will most likely not work due to their big NAND flash space. (Of course, you can try if you want).
iOS 10.3 introduces a new File System format, so if you get errors about opening the DMG in TransMAC this is likely the issue, TransMAC requires an update. PowerISO is also able to open DMG files as far as I know, either way, until updated, try on OS X (if on Windows, use VirtualBOX). If your computer isn't decent enough to be able to run VirtualBOX (at least 4 GB of RAM) then that's no longer my problem. Make sure you read the F.A.Q. page! If you want to understand more the Setup.App and how it works, I attached a documentation link.