When I do a switch (obviously good clean and extra rinsing under the rim as well, I use baking soda and vinegar btw) I will do a filter clean and then a couple weeks later do the switch so as not lose too many BB, the 2 weeks helps get things closer to normal.
Take out the top half of the water into your bucket.
Then remove the plants, decor, wood, etc and shrimp to your bucket with the heater and filter if you can set it in there on a rock or something or just the filter media in the water.
I do a gentle rinse with treated water swirling it around just a bit and rinse a couple times - then into the new tank. If it really isn't very dirty you can do the rinse once. Reminder to unplug heater and not forget to replug it back in later!!! Not that i have ever burned out a heater or forgot to plug it back in or anything :EEK:
Then just put things back into the tank from the bucket, including the water. Then the shrimp, then slowly add water back into the tank. If your tap water is majorly different from your tank water more slowly, like acclimating the new tank. If not really different then not as much to be concerned with. Personally, my water is softer in my tanks than straight from the tap so I would add the rest of the water more slowly over a couple hours. (or save more of the tank water to start).
Want to see some pics of the new tank!!!