Always build depending on what the enemy team composition or what your team needs. If you team is squishy, obviously go tankier. Or if the enemy ap mid is fed build extra MR, never follow a guide item by item.

The Ryze change is very new, but if you read how his "E" works now, he can be very handy in the jungle Always initiate ganks with his snare. And try to build a bit tanky every game, as a standard ryze build. This is a new concept for everyone, so experiment with Ryze jungle a lot, and I can guarantee the results will be good.