Not speculation, xiaNaix been in chat with the makers of E3 and I going to personally test it on my v3.50 slim the moment the files are available.
All you need is "SERVICE MODE!"
Once that happens you can use those previously leaked DGF.RAR file with the modded v3.41 PUP and the two .selfs and just follow the normal steps of downgrading, and turning off service mode!