Hi Jinks
I grown up in a village and my grand dad used to have vine yards.
Exactly what he did was using the big root system and the strongest branches from new growth of the grape.
Planted another type in it to spread two types off grape from one big main root system.
And this is a close way some grapes have been modified and probably still modified today.
He looked for similar sized branches for a mum and the baby.
He used just cutting the branches at 45 degrees angle and tide up both ends mum and baby with electrical tape and with extra 2 support sticks along both Baby and mum where they are connected, with tape again in 2/3 weeks you should have all one branch.
For humidity and warmth to be kept inside he put around cloth and moisture it little daily.
That's a 80s method and I don't see a reason it won't work on Photoperiod Marijuana.
Hope this helps and good luck with grafting some beauty.
Happy Growing
