Not a bad guide I personally play 8/0/22 on masteries. I use ignite ghost so I train them get 3 ap and the 4% cd. I dont get the summoner ability cooldowns on utility I get the health regen per mana since Ryze stacks mana to all hell. If you drop Sage Mastermind and Arcane knowledge you can get the 1% mana as hp5. I use mana runes all around I get 102 mana per level which is great early game. Instead of getting pen boots I get mercs to escape those ganks or keep fighting after stuns.

Item order Mana Crystal->Tear->Basic Boots->Catalyst->ROA->Mercs->Manamune. At this point youre probably level 12 or so and you will have 200 ad 3400 mana and like 2200 health. This will make you a huge threat at that point in the game. Then I go Frozen Heart which maxes your CDR Banshees Force of Nature and then Archangel selling boots.

Final stats:
306AD
431AP
180Armor
156MR
3149 Health
5763 Mana
22.55 Health Regen per Second. 112hp5 this allows for great escapes or just a chance to walk away and rejoin when they find someone else to focus. Overall your guide is great for those getting used to Ryze. Great build!