for the second i dont care qbotu

Rylai's is no good on Singed...there are like 10 different items that would work on him better.
You get it for the slow, but it on procs on two of his spells. Poison trail for a measly 15% and fling which is in the 1.5 second duration even when the enemy is in the air. Just a poor item...leave it for a mage that it works on.

Sorry forgot to vote :)

This is an interesting build, I would replace the rabadon's with a more tanky item and change masteries to 0/21/9

You should fix your rune setup ^^