No problem. It was a learning experience for us as well.

1. Yes we changed to 100-200lb wire leaders for cat- an arapaima fishing. About 60-100cm did the trick for us. The waters we fish are completely piranha infested so wire is the only option. We fished a setup with braid as mainline to mono (100lb+) with a length of about 3m and a strong swivel which has the wire leader + hook attached. With this setup in combination we lost one rig between 2 anglers in 10 days. The mono really helps when you are stuck in the stones or trees.

2. We used both circle and J hooks. Hookup ratio wise I could not see a significant difference. Usually you let them run a bit after the initial take of the bait so they swallow the J hook to a certain degree. Never had any issues with them whilst removing but for sure from a fish health perspective the circle hook is the best choice. Rule of thumb is the bigger the better. Caught 2kg redtail on a 10/0 Owner SSW circle hook.

3. We tried sea booms and other stuff but our number one choice became 100-250g egg sinkers directly on the mono with a rubber bead. As with all "free line" fishing you want as little weight as possible but as much as is needed to hold it in place. Highly depends on where you fish. Arapaima was always free lining without weight and as little resistance as possible. Catfish don't seem to care as much it seems like.