Twisting the earths together , eh not seen that done for a while.
As for stripping T/E .... snip the end , grip conductor, earth and half the sheathing with sideys, grip other conductor and sheathing with hand and pull apart .
Also rip the earth wire down , never encountered a problem with it being "stretched" I think thats college talk TBH.
Some of the 10mm and 16mm is tough stuff , run Stanley down the sheath, in the centre , where the earth wire is.
As for stripping the conductors, I use CK sidecutters with the notches in , or an old pair with a 2.5 blow hole in them .