@MissFrodo I used a combo of flushable and fleece liners. I'd use the flushable when I knew / thought he was going to do a poo, I always cut them down though as found them too big, in 1/3 when he was tiny then in 1/2. Once solids were well established I found the poo generally solid enough to roll off the fleece, I'd use a bit of toilet paper and I seem to remember I had an old knife that I kept by the toilet for bad ones!
BF poo just rinses out of fleece liner