OK, cool, but why? Have you done both and measured both? As I said before, I'd be happy if someone can save my time and effort! Also, if that is the case, why have HH's been going for hundreds of years? I agree loose stacking is important - the HH I read says ensure a mouse can run between splits - but I think the method is important too. I will do my best to stack both the HH and the comparison rows with similar gaps - if I do this and the results show the HH is superior will you believe it? Please, I'm not knocking anyone's experience, but I want to try and scientifically measure this and try and determine if an HH is better or the same or worse as normal stacks. I'm still keen for feedback, advice and suggestions on my experimental method, or proof by others who have done similar to save my time and effort.