[cypher]

That wheel should be fine really as long as it's big enough for him, it should be but hams do differ with what they can run comfortably in, some do seem to prefer an enclosed wheel so you could perhaps try something like the Trixie wheel (from Zooplus) if you want to experiment a bit.
If you scatter food on the surface it usually works down into the substrate fairly quickly anyway once they start to dig around so you don't really need to do much else.
Hope he enjoys it & gets a little more exercise!