Conditionmancer Sigil?
Energy is good for the staff. Gives you an extra dodge.
I would not use Earth Sigil on Staff, in my experience, and after extensive testing, I have found it bugged. After the first weapon swap in a zone it would just stop ever procing. This is hard to notice because your barbed precision would still trigger (1 sec bleed) but never the 5 second one from the sigil. Possibly build related bug, but I would suggest testing yourself.
I use Sigil of Battle on my staff, 3 stacks of might for 20 seconds, which will help both your direct damage and condition damage, and will still be going usually when you switch back to scepter, whereas most sigils will do nothing for you once you are off staff, and as you noted, you usually are not on it long.
If you want to stick with bleeds, Geomancy is a good alternative to Earth. However, as Staff is a long range weapon, I found that often the bleeds will not hit anything as the radius is rather immediate around you (about like a well).
(edited by Pendragon.8735)
I’d suggest something like Corruption on the Staff.
Due to the way Sigils work, as in Sigils that have a cooldown (On Crit and On Weapon Swap) will not proc if another sigil is on cooldown.
This means that an “On Swap” sigil may not trigger if you’ve just procced the Earth sigil on the Sceptre.
While on the other hand something like Corruption can help keep stacks increasing if you swap weapons.
Failing that you could always put an Orb/Crest on it for more stats (I do that with some classes whom only use certain weapon sets for utility rather than a main damage source)
There’s two kinds of people… The quick and the dead”
I go over sigils and runes for several condition necromancer builds in my newest video tutorial. Here is the link to the forum post.
http://www.youtube.com/GibblyGaming
http://www.twitch.tv/giibbly