Honestly its better to go for farm speed in t10 and clear higher/faster to the point where the db farm can actually be more efficient. Either way tho db farm is a secondary thing, you pick up DBs along the way while farming grift keys at max efficiency. In the long run Grift Keys > DBs
I disagree with chainer on that point. sage set can still be usefull for very casual players. I do not play enough so that I don't need a lot of GR keys. But I need of lot of Death breath to get my stuff, because even in the course of an entire season I'm not fully equiped with perfect stuff.
I personally use this build to farm. It can be optimised, but works well like that for me. Not ultra fast, but quite fast to clear TX and get tons of DBs
This is the build I'm using. It's strictly for keys and like Chainer said you pick up DB's along the way. Sure you could equip sage and get about 1000 DB's & 30 GR keys every 70-80 minutes which is what I use to do but honestly it's best to farm Keys as fast as possible and pick up what DB's you get. Right now I'm averaging around 30-33 keys an hour and around 300 DB's.
I haven't run into another TX speed build that's faster. The only build that I've played with that can kind of keep up is flash fire Wiz and honestly if you have all the stacks up they can't keep up.