I'm going to update this guide. The build above isn't meant to be definite and as I continue to play Cassiopeia and this game I learn that having a definite build is impossible as you have to account for all the variables in LoL. As for the build I have presented, It, like others has it's disadvantages and advantages. For instance, the heavier spellvamp very well versus Low CC/ Low MR base teams and is a lot more effected in providing sustain over a zhonyas or RoA, how every it fails very hard versus offtank teams. I wasn't too thorough in this current version and will update it to be more informative with different paths and suggestions.

for your LoLReplay issue: use fraps

Otherwise I think that having high spell vamp is great but you sacrifice too much damage buy leaving just a revolver as a final item slot, increasing survivabilty with zhonyas active and armour is much better for your damage output. Asking the another AP hero on your team to pick up a will of the ancients for you is often a strategy to drastically increase your spellvamp without sacrificing damage.

Maybe this revision will be a little more kind on the eyes.

It's kind of hard to read with all the big icons in the text. When inserting items in the middle of a text, use name instead. Try that? D: