I've been using runes/masteries that Nightblue3 uses for Elise... I don't know if they are optimal but seem to be working for me!
Runes:
Ravishing - Runes
Magic Pen.: +7.8
Health at level 18: +120
Armor: +4
Cooldown %: -7.5%
Ability Power: +14.9
Masteries:
Ravishing - Masteries
21/9/0
Note: First clear using these runes/masteries is SLOW. You will take a lot of damage from Red/Blue.
Be VERY safe early on. Try to get a nice leash, let support take damage from golems/gromp for you, smite after they leave so they help do as much dmg as possible.
My typical first couple clears are:
Gromp or Golems -->> Red or Blue -->> Scuttle crab (if you see enemy jungle, RUN AWAY).
After Scuttle you might be able to do another 1-2 camps depending on your leash (wolves, wraiths, or golems).
BACK > Buy jungle item > RED or BLUE
Ekko can gank nicely pre-6 but you are squishy until you can get your get out of jail free card (ult).
CDR on Ekko is actually awesome. E is awesome and it will be on a 4 second cooldown at max rank with 40% cdr. Typically skill R>Q>E>W.
Usually I wont get 40% CDR but will approach mid-30% with FH and blue buff will get you capped whenever u have it.