I scrub my filters with a green scrubber, rinse, and put them away. They will dry on their own. My filters, Katadyn, are silver impregnated. Some Berkey filters are also. I surmise that is how the feds declared them pesticides and tried to stop their sales.
My filter body holds 4 filters, I plugged three holes and only used one filter. That provided plenty of water for the two of us. Unless you are running short I'd use the old setup. You could also move your current filter to the new body, plug the extra holes, and save the new filters as spares.
If making a 5 gallon bucket filter I'd use 6, or better yet 7, gallon buckets. That will increase your storage, and place the filter lower in the water increasing recovery time.