I just did my research into FIMing and I found this picture, I thought I would put it on here as I found it to be much clearer than the photographs that I mainly came across

Fimming vs Topping

Just so I'm not taking credit for it, as it is not my pic, I found it posted by a member called DierWolf on another forum (Dont know rules about naming other forums on here so i haven't).

Makes sense to me so I think I will give it a go.

Just out of curiosity, can you 'FIM' the secondaries?

I have 6 lots of secondaries on my plants now, It seems like quite a lot considering their age and height. Is the time right to FIM if I am going to?