Hi Robert,
That's something we can think about - as you say, it could be very useful and I don't think it would be too much work at our end. I can't give you a good idea of when we might have it available, though.
In the mean time, I would suggest entering one or two tide points by hand for each of your tracks. You can do this using the Manual option, and if you enter e.g. a height at the beginning and end of the track, then the tide depths in between will be interpolated between those two heights.
Matt