Affliction lock in instancesFollow

I have an Affliction lock working his way through the 50s.
My normal style of solo play for many levels now has been drain tanking with the Succubus.
So basically Curse of Agony, Corruption, Syphon Life, Life Tap, start Drain Life cycle.

In instances (and it has been showing as early as Scarlet Monastery) I don't do a significant proportion of the damage. It seems that the mobs don't live long enough for any DoTs to get some ticks away.
If I try to use my normal solo cycle, that's 4 GCDs before the damage really starts stacking. That's normally the life-span on the skull mob. :-)
I haven't been bothering with CoA, takes WAY too long to kick in with decent damage.
I have been resorting to just Corruption on a few mobs, then Shadowbolt or wand.

Is there a recommended method for spells, that can increase the burst damage done?
Is it worth firing off Siphon Life and Drain Life when I am at full health?
Or should I try to keep my health level at 1 or 2 lifetaps under full?

For my gear, I try to put Stamina at higher priority than Intelligence, plus shadow damage where I can. It's a bit rare before Outlands, but I have a couple of pieces of the Shadoweave set, my +shadow damage is about sixt-something. Can't armory link right now, work firewall won't let me.

Thanks.

That.
Spam SB on trash, but watch aggro (maybe get Omen or some addon like that). Maybe put Siphon Life on em to get a bit of extra health back.
DoT to your hearts content on Boss's.

Not to be an *** but do you have some WWS stats to back that up?

I also run as the raids only affliction lock, and with 1401 +shadow damage running T6 content I see nowhere near that high of DPS. Maybe on a multiple add fight, but not when it involves a single target.

I generally average 1200 DPS, raid buffed, love to know how you are hitting 1500.

1200 is the norm for our guild pre party buffs. I have seen 1400+ with the right food, items, and buffs myself and my lock is just in spell strike / frozen shadows still. ( maxed enchants though) I can see a 1500 with better gear with ease.
As for aff in instant / raid runs..SB and maybe 1 or 2 DoTs is your best pre-boss way to go.(UA improved CoA for me, but I have a unique play style) On a boss drop your dots but keep your sb in the rotation.

Use SB on trash with over 50% life. Once you get below 50, that 3 sec. cast time sometimes runs out, when you could be gaining a shard, or draining life after a lifetap.

I'll bet. I split duties in Scholo with a fellow lock. I hit the caster with Curse of Tongues, while he used Curse of Shadow and we both spammed SBolts. It was gruesome.