Yea, 28 hot??? OMG, thats scary on the R6s. That mUST be a slick pressure.
Its hard to suggest proper cold starting pressures as each corner will build differently, depending on car setup and track. And weather.
Also, I think the 205 /60 isn't the best choice of sizes either, but the choice does involve the rear gear so, we'll leave that for another day.
If i were starting fresh, I'd probably start around 32 on a hot summer day, and shoot for 37-38 hot. They are squirmy and slippery at 32 and cold. You will probably end up at 38.5 to 39.5, they build about 7 or so, typ. After adjusting, you might find that you end up with one tire starting at 30.5, two at 31.5 and one at 33, depending on the track, setup, etc, to end up with 38 at all four corners.
I had a crew guy screw up at Summit Point once and we started WAY too high. Wound up at 42 hot. Lap times suffered and it was all I could do to hold 2nd place off late in the race. One more lap and I was toast.
So, 42 hot is TOO MUCH on a first gen.