I have worked with KoF in the past (evocation), but would like to try and work with the entities therein via sigil magic. My question is, would one still need to open the square first prior to opening the sigil of the chosen entity? My guess is yes, but if you’ve done it differently (with success) then please feel free to share.
C9
I reckon it’s possible to contact these spirits without first opening the specific KoF square. I’ve tried both ways and I had no issue making contact with Deggal, for example without first opening the Kingdoms square.
You dont need to open the squares.
Ive always used the sorcerers seal with kof sigil magick but not the squares.
Do you mean you use the seal as a sigil or just wear the seal during the ritual?
I open it first then the sigil.
I did a sigil opening for Ladilok and it took a while to work but it did. 
To add to that, Ive noticed that whenever sigil magic is used (I dont evoke yet…or havent tried anyway) the demon brings you exactly what you didnt even realiz you wanted! You have to be very specific about what your conscious mind wants lol