“Use good quality hard or soft household toilet paper, but do not use more than necessary.”
The above is from the Jabsco manual. I have never had a marine head actually clog on toilet paper. Clogs I have had were other issues. The biggest one is that the hoses after the head calcify and diameter is reduced. This eventually will lead to clogging. The other is the thru hull getting blocked or partially blocked. My standard charter routine is to dive the boat at the first anchorage and check for bottom damage and that all the thru hulls are unblocked.
On Moorings boats if a head does clog before you call the Moorings open up the access to the holding tanks. Very easy on a cat. Find the inlet hose to the tank from the toilet. It feeds into the top. Grab and shake/bang aggressively the hose. This will solve many clogged heads. If the same head keeps doing it and this fixes it it’s calcified.
I have very few head issues overall and we flush TP. I do however brief two things. Minimum use of paper and extended flush times if paper is used to insure the paper is through the outlet hose.
P.S. The number 1 cause of toilet clogs are baby wipes. Even those marketed as flushable can’t go in a marine head!
G