Great question!
It’s good to see you're taking these solvents seriously.
P1 protects you from dust and other large particles. It’s not for solvents.
The P3 filter is the best. I would use that. It protects against nearly all known chemicals.
HINT: if you can smell the solvent while using the mask, the filter isn’t filtering it out.
I own one of these and I always use a P3 filter. With that, I can't smell any solvents at all. The air smells perfectly clean. Even something really smelly like xylene can’t be detected while wearing the mask properly.
If I’m dealing with a lot of solvents (like when cleaning metals or chemically welding plastics) I always wear one of those, even if I’m doing the work outside. If you can smell the solvent, you’re breathing it into your body. So anytime I feel I can smell the solvent, I’m putting the mask on right away.