Slow Pulled Pork Help

[ICEx21]

Morning folks, I'm currently attempting Platypus's slow pulled pork recipe but I'm a little lost over how long I should put my joint of meat in the oven for and at what temperature?.
He used a 2.5kg joint where as mine is a 1.34kg joint.
Could anyone help as I don't have a meat thermometer either.
Many thanks for any help

 

[ICEx21]

Ok I get ya, I decided to put it in on gas mark 1 and after 3 hours checking it every so often.
How does that sound?