Twitchy or on edge is subject to where it feels that way, because different things can make it edgy depending. With diff oils, more so in the rear, I personally feel lighter oils make the car feel unstable going into corners, so unless your fighting really low traction conditions, thicker rear oils make the car more predictable on corner entry.
Running a front diff seems debatable in the pit bench trash talk between heats, some like it, others hate it, you probably can't deny a spool will always give more drive, but I like the steering and mid corner agility, though I also like a front diff that also still works like a front diff, so none of the near lock up million weight oils etc.
Everything is subjective to how you drive though, and how much power your trying to put down.