When you say your chart is for seed stitch do you mean that it is simple seed stitch all across the row/round? or is it a more complex pattern stitch with some seed st involved?
Like you I learned that the first row after a long tail cast on should be a purl row, that keeps that little edge that looks a bit like a stem stitch in embroidery on the knit side (right side), but I see a lot of patterns that make the first row the right side. If you really are doing just a basic seed stitch and then perhaps changing to something else, is there any reason why throwing in one more row of seed stitch to put the edge you like on the right side would hurt anything?
Another option would be to purl a row and then start your chart.