Do you try the obis/gorget ones solo? I'm about to attempt with a group of people and we don't have many with synergy maxed out. Any additional guidance would be greatly appreciated!
I can't say this is the best way to do the obi synergy, but you can pre-craft Light and Dark fewell for people helping (regardless of their synergy skill as long as they've unlocked it). Have one person spam the operation that heals the furnace. Have one person spam the operation that reduces pressure. If you have another person, have that person spam the operation that reduces impurity (otherwise, you do this after several feeds). Balance out light and dark feeds first. If both aren't within acceptable range at this point, tell whoever you're doing it for to end the synergy and start over. Then just do the other feeds. If you have a leak, tell people to slow down when you get close to target, since each action procs the leak.
If you're solo and you get leaks, all actions you take to correct it after the fact will probably just get you farther away from success than closer. At least, that was my long, embarrassing experience. The two obi synergies after that went well.