Update : The diet isn't working too well. *1/2 dry , 1/2 wet and
there's a mess to clean each morning, outside box - not quite diarrhea
butttttt..........close. *I might be going away and don't expect the
catsitter to have to deal with this, * I'll set up two boxes and put
him back on dry until I return. *Then will introduce the canned food
at a more gradual pace.
I'll also try giving wet in the morning and dry at night. *I was
feeding the reverse.

What brands are you feeding? I read through the posts and did not see
a mention of brands. He should be eating a grain-free wet if at all
possible. If it's a high-quality diet there should not be any stool
problems. I didn't have any when I transferred mine to wet food.