There was a discussion of graphite bottom coats in the thread on coamings (DS1 forum). Perhaps we can move this here and generalize it a bit.
What things have you tried to make your bottoms faster and do you have any evidence it worked?
When I joined the local all-comers beer-can race (not sure why it's called that way, I've never seen cans, but they do give away beer once a year), I was taken aback when one of the competitors reached under my hull to check it for smoothness. What he found was that the state of the (painted) hull had deteriorated to the consistency of sandpaper. The coating had failed (undetected by me) and created several really rough patches, all of them where they were nicely out of sight.
So, thinking that this might explain my last-place finish, I careened the boat, sanded off the paint, fixed the gouges in the gelcoat, and brought all the patches to the same condition as the surviving paint around them. The boat felt a lot faster and I was still coming in last.
Next, I went for a complete redo. Sanded off all the paint, fixed more defects, added fairing compound to smooth out medium scale waves and bumps. Painted with a PU topcoat. The result is that the boat looks great (from below) and feels a lot faster. I'm still coming in last.
At the same time as the first bottom upgrade I had unearthed a really banged up CB which I refaired and re-gelcoated. That stopped a noticeable flutter at high speeds. Since I had been coming in last, I decided to improve the rudder. Since that didn't change anything other than make the rudder much lighter and nicer looking, I used the second pass over the bottom to further improve the CB. Alas, no change in results.
Now I bought a different, faster boat and found some expert dinghy sailor as crew, and that fixed things (fourth place).
Of course, the real problem with the DS was that it was outclassed by the other boats, and in a no-handicap race that's the end of that. Except when luck, traffic or what have you mixed up the tail end and I got second to last.
Coming back to the question of a faster bottom. Unless you sail against another DS, I don't see how you can actually observe any improvement. It might be there, but conditions are too variable (wind, waves, trim etc) to allow one to tease out the contribution by any one factor in a single boat test. That's why hulls are compared with towing experiments using towing balances where differences in drag between two hulls can be observed in real time in the same conditions.
It might be possible to notice some effects when racing another DS, but my suspicion is that you'd have to two pretty expert sailors to be able to attribute any difference to such a single factor. That's why I included the question of evidence above.
So, what have you tried and what are your results?