A Few Questions On Making Sigils.

alrighty. I know what sigils are, what they do, how/why they work, and even how to make them. however there are a few things, do's/don'ts if you will, that I don't really understand. or rather I don't understand why they're do's or don'ts when making a sigil. so, here are a few questions

writing sigils as if they've already happened ("MY SPACE IS CLEANSED" vs "MY SPACE WILL BE CLEANSED")

no clue why this is done.

writing sigils with negative words in the intention ("MY SPACE HAS NO NEGATIVE ENERGY" vs "MY SPACE IS CLEANSED")

no clue why this is done either

why you should keep a sigils intent kinda short ("MY SPACE IS PROTECTED AND CLEANSED AND SAFE" vs different sigils for each of those intentions)

this one I understand a little. it could be that with a more blanketed sigil you take some focus away from other parts of it. a sigil made with the intention of keeping someone's space protected, cleansed and safe, might be weaker when compared to 3 different sigils made for each of those 3 things specifically (protection, cleansing and safety). however, I don't know this for sure and would like another person's take on this as I could be factually wrong in my assumption.