For the Ashen ring, it all depends on which spec you want to focus more.
If you mainly want to be a FDK DPS, the best option might be to get BoE icc trash tank ring instead of the ashen one.
If you want to tank and you have no other ring, Might of Blight and Skeleton Lord work just fine.
As for your gear...
20 hit on Gloves, 12hit12crit on Feet.
Yellow gems in: Neck, Cloak, Wrist, Belt, Ring1, Ring2
Should be 10str10hit (or 10str10haste depending on what ring you chose as your 2nd one). Yellow gem in agil gloves and other agil items should always be pure 20 arp.
Red gems should be 20 arp (3x 34 from JC) all the way.
Blue gem in chest should be matched with Nightmare Tear (T10 legs should be gemmed with 2x 20arp).
Meta should be Relentless one, 21 agil 3% more crit dmg.
Hit number you want to be at is 164 - 263, no more than this.
With Ashen ring, you will have a choice btwn 3x 20 arp gems in yellow slots (wrist, cloak, neck or ring) or 3x 10str10haste gems. With the rest of yellow gems being 10str10hit, you should be at 262 hit.
Without Ashen ring, all yellow gems should be matched with 10str10hit to reach 233 hit rating.
Now, for expertise cap...
If you ask Rifokelt, he will tell you to abandon Skeleton Lord ring and go with 17 expertise.
If you ask me, it all depends on your skill level. If you are confident enough to know that you will make it on time and always refresh diseases with pestilence while getting dodged, feel free to do so.
If you are not so confident in your rotation skills, keep Skeleton Lord ring and maybe gem it with 10exp10hit to reach 26 expertise.
Again, Sigil of Awareness is a must.
There are couple of rotation videos in the guide on forums that i advise you to go check out.
While we are at it, check the guide for spec aswell, the one you are using is not great to say the least. :D
Learning the rotation and how to move, switch targets should be your top prio now. There is the huge text and multiple videos in that guide that can help you a lot. Take your time and practice. I cant repeat this enough cos it is the most important thing when it comes to FDK dps in case you want to be at the top.