Want to fork FLF, where to cut?

Spring time is around the corner. My FLF is about 5 feet tall and very sturdy. I would like to prune it so that it will fork. I have tried notching multiple times last year without success of any new branches. Does anyone have guidance on where I should cut? I have read to cut at a 45 degree angle just above nodes where you want the fork to be. Is it that easy?

There are two main stems connected just below the soil line which looks like a completely separate plant. I bought it like this. I am unsure if anything should be done to the second stem as it is the smaller/thinner of the two.

I have it potted in a plastic insert 8” x 10”. This will be the second season in that size pot. Do I need to upgrade the pot once I make the cut? The roots don’t seem to be crawling out yet.