So I hit 600 in the delve, actually at 710 now. Just upgraded some gear and added a shitload more attack speed to my build - I cannot be behind the crawler now, I have to be ahead killing the stuff as it appears on the screen or i'm dead, and forget city nodes, so i'm stopping. On a good note, any map mods are a breeze in comparison. Been wild and i've wanted to chuck my computer in the bin at points.
I started buying scarabs at 80 and went straight down to around 550 then some mods were becoming pretty intense so had to move sideways sometimes.
I don't know how many scarabs i've actually used but I had around 4ex when i started to just Delve and T16 to fill up bar, no other maps. I ended up with 24ex, 3k chaos after selling all the shit (fossils and drops, no maps). Had 3 void batterys alone past 600 and some other high end drops.
Been great.
Also I met some guy who crafts so he takes all my fossils which has really helped as I dont' have to stand around dealing with people trading which is a pita.
Edit: I also bought all my gems nearly at level 21 as none of mine corrupted well this league, and that really really helped with my dps i think.