I have talked to many Sages on the Harbinger and you are about where the rest of us are. I do a parse or two about every day and my average is around 1740 over six minutes in full balance and slightly higher in TK without the armor debuff (I am full dread guard, and have been for some time). My highest parse is 1841, but got lucky with the crits on that one.
I also try to parse in the morning before work and on my ship. I parse as much as 30 DPS more in the early morning (when few are on) than I do at nighttime and nearly 75 DPS more using the dummy on my ship than when I use the training dummy on the fleet. I've been quite surprised at how much of a difference these two conditions make.
You might already be doing this, but I try to deal with lag this way:
1. Change your action queue to 1.0 seconds under preferences
2. Queue the next ability mid-cast on the current one
Since the server already has already received my command for the next attack, it will fire it off on-time even if there is lag.
This doesn't work after channeled casts, as the next ability will interrupt the channel, but it is ideal when waiting for the gcd to finish.