I live on a tidal river and fly a small amphibious seaplane--so tide height is important to me. Your tables for the James River in Virginia, USA, appear to be quite accurate as far as the times are concerned. Tide height here is heavily influenced by wind, however, so the heights predicted by ALL tide tables are notoriously inaccurate. I think the only to improve them would be to factor local surface wind into the equation. I just do it by feel: if the wind has been 10 knots from the northeast for a day, I figure about 10% more than the tables predict. If it's been two days, 20%. And so on. But those are just very rough guesses. I've never actually measured wind water to be sure of anything. Anyway, I really like your tide predictions!