I just posted this in the C MH section, having to do with dry camping, but it applies in this query also.
I have a 2 gallon bottle of water (old laundry soap container) to partially fill the toilet.
1. It's faster and easier to charge the toilet by pouring water in, rather than dancing on the foot pedal.
2. I use that same container to rinse the black tank after dumping and also to put a measured amount of water in the black tank.
3. The laundry bottle has two openings, so empties very quickly.
4. Saves using fresh tank water for operating the toilet.
Norm