I agree with will, theres not much spring left in the torsion set up when you have the head fully wound up ..I was nervous too when uncoupling it but it was easily held with one hand strength..you can use a spanner or something similar to give you a bit added purchase to hold it from springing out but really there is'nt very much ping left in it when you have the head right up,, thats probably why most people have trouble with the head dropping when its up high,,,I'm sure the heads of the x2's are around
15-17kgs and thats why the usual strength of gas strut for this mod is 150n to 170n,,, I used a 300n one which is way to strong and rolls the head back up if i don't slow it down with the drill handle,,,i have a 150n one to replace it but have'nt got round to it yet...I use a 20" overall length of gas strut but others have used shorter ones ..Lyn, you wont be able to get any movement on a gas strut until its fixed to something solid then lever action is applied,, i'd suggest that if you can get movement on your strut by just using your hands, then it's probably no good...hope this is of some help,,oh and use steampunkpetes maths for working out the sums,, he knows what he's talking about,,,
..mike..