“I’ve read that LST must be stopped when flowering, because that could stress the plant.”
There is no need to stop LST in flower. Supercropping (bending plant stems) is very common in flower and it helps solve the exact problem that you have.
"I’m scared to cut it also !”
Are you talking about “defoliation”? That’s part of growing plants. Some growers defoliate heavily, others argue that you should only remove leaves that block air flow or that are blocking light. I typically “clean up” the foliage that isn’t receiving much light because it can’t contribute to photosynthesis. My threshold for that is < 200 µm.
As much as this is a handy forum for discussion issues with the Pulse, I would recommend that you look at other fora that have a much larger membership. I regularly read 3 other sites that, between them, havens of thousands of members. They’re an excellent source. Also, sites like groweedeasy.com, and ilgm.com have step by step tutorials on growing cannabis.