your problems probably the cheap £8 headgasket lol mine blew through a while back get a genuine one for £20 and bolts were £38 all genuine
yh for tensioner i either get circlip pliers or hook 2 allen keys in and use one against the other for leverage lol never in all my years seen anyone use a gauge for any tensioner you can tell when its right...dont over tighten you will get a squeak aha