hat is the best way to set up a session using DP and be able to create a headphone mix and a talkback device?

I was doing a session with DP3 yesterday. My system is as follows; G4dual450,Ultra wide barracuda drive MOTU1224, 320MB RAM. I was trying to track vocals so I set up my preamp to go directly into the 1224. Most of all the other tracks in the mix were already cut on ADATS and bounced over. So I was running about 24 tracks when the vocals were being done. I had a few plugins running and various tracks nothing to major. It wasn't taxing the system in the least bit. My plan was to use the sends in DP to output a signal to one of the analog outs and run this into my headphone amp. What I was getting was a major delay in the singers headphones. The cable run to the headphone amp is long I would say 40'. I tried adjusting the buffers in the hardware setup but this only slightly minimized the problem.

My next dillema was how to communicate with the singer. For a talkback I set up a mic into MOTU as a pretend record track and when we were ready to record the singer I would take the mic out of record mode. This worked finebut obviously was rather annoying everytime to have to take a track in and out of record.

I also have at my disposal as Mackie 24x8 and a Mackie 1402. I was using the 1402 as a way toadjust my volume in the control room. I did not want to use either board as a means to get a signal to record into MOTU as I have some nice preamps and would like to get a more direct path into MOTU. Also I still think I may have the same delay problem either way.

Any suggestions? What do all you do with your setups, what do you use?