A few general questions from a new s6 owner....

Hi, I wanted to ask a few questions before I start tinkering. I'm on stock 5.1.1. With uni kernel and root.

Question one.
What is my best options for creating a restore point to flash in twrp should anything go wrong? Trying to find something cloud based that I don't have to keep on my phones memory.

Question 2.
Anybody tried this rom on g920p and can conform working?
XtreStoLite_ROM_v2.2_XXU2BOGG_S6_G92xF-I-T-W8-K-L-S.zip

Thanks for any help in advance....