[DutchmenSport]

Rather than replacing the entire toilet, why not just switch out the seat?



We also installed a Bidet:







Also, the reason for keeping the black tank drain valve closed is so you do not end up with a poop pyramid in the bottom of your tank. Solids will pile up and the liquids will drain away if you leave the valve open. After a while, there is nothing but solids and those solids will block the tank completely. Eventually, (and it doesn't take long), the entire tank is a solid blob of "solids" and it will never work again.

If you install a residential toilet, then you are best to remove the black tank.

You are looking at a lot of work. Switching the toilet seat is a lot easier and cheaper. I got my seat from Lowe's.