The problem is that if you don't use the proper amount of water from the first use and damming or pyamiding starts to take hold, you need to break that up for things to work properly once you do start using enough water.
The black and gray tanks on my Magnitude run side-to-side across the coach with the deep end and drain on the drivers side. The toilet is on the passenger side, which is the narrow end and I have never had an issue.
Most people don't use a standard RV toilet properly.... and the proper way is not boondocking friendly as an FYI. Here are my "rules" for using an RV toilet properly.
Rule #1 - One full bowl of water when going #1! While you don't need this much water to flush it promotes good draining and washing toilet paper and other "debris" down the tank.
Rule #2 - Fill the bowl with water first before going #2! Flush before wiping. Fill bowl again, wipe and then flush, This provides enough water to keep things moving down the tank and not building up under the toilet. If you want to be safer than sorry, then flush one more bowl of water when done.
When I dump the black tank, I use the San-T-Flush to fill the tank once or twice ot make sure it is flusing 99% of the debris out of the tank. I then add a couple gallons of water and the DW pours some Calgon Water Softener, Dawn and a treatment tab down the toilet.
We have never had an issue with the black tank in our coaches and we have always had the toilet on the paseenger side... furthest from the deep end of the tank and drain.
If you don't like my rules, then you are going to have issues so you might as well purchase a macerator toilet like this one.....
https://marinesan.com/7640-rv-master...gn=besttoilets