I've picked in warehousing but never in breakpack, but I've been told by a team member that they even though they struggle to make their numbers when flexed to warehousing, they always make their numbers in breakpack so I'm assuming breakpack is more forgiving when it comes to production numbers.
I'm not trained in breakpack and I've only ever flexed to breakpack to feed. It started one time on A2 when someone else from warehousing groaned because they didn't want to do it "AGAIN!", so I volunteered. It's boring as hell but easy as pie. There were 2 of us. One per side, about 4 packers per side. The other feeder left. I can't remember if they went home sick or what... but I ended up working both the Hardline and Softline side. The key is to slice open boxes and stack them up with the breakpack labels facing up or facing towards the packer. If you get started with a "hot handoff" or in other words, the last shift set you up to fail or didn't set up a line that is now running, have no fear. Just be methodical. Go to each line. Slice and stack until it is stuffed and pushed up against the packer's elbow. Go to the next line and repeat. You're way better off setting up each line with a ton of work because if you only give them a little, you'll be running constantly. Giving them alot means you have time to keep the line built up, get more boxes for them if they need, stack up your pallets if you have freight on wood, and most importantly, keep pulling carts up as close to the line and you as possible, because the tuggers can have a habit of only putting new carts a mile away from you if the line of carts isn't constantly pulled up close and tight to the packing mods. But Tuggers are swamped too, so... not always their fault.
Good luck.