I wouldn’t worry about the tank unless you have an issue. As long as you know how to use you’ll be fine. Just check yourself with fresh water first. Add some water to both tanks either through the toilet and kitchen sink or via hose to the flush point connection. Connect your slinky and drain the black first, then the gray. Practice at home if possible or as soon as you get to a campsite. Use TP that breaks down quickly and plenty of water in the toilet.
To check your TP, put 3-4 sheets in a glass and add a cup or more of water. Put your hand over the top and shake for a few seconds. Suitable paper will almost dissolve. After you’re comfortable with the use, ensure that you keep the drain valves closed until you need to dump. Never leave the black valve open. I leave water in mine even when not in use. Keeps any remnant from drying and turning to concrete.
2006 Gulf Stream Friendship G7
350 Cat, Crusier Lift w/ Honda VTX
Blue Ox and 2019 Chevy Blazer RS AWD V6