Thanks all. Some new WIP's; with larger trees on the islands (mmm), just shrub (better), and a change of sunlight to evening. Used a voronoi island setup this time, mixing 2 sizes and a PF mask, with some adjustable smaller 'cross-bar streams' (cracks, basically). That works a bit better. I think less waves would be nicer, and smooth reflections of course.
They still render pretty quick (1hr) at 0.6 AA6, soft shadows, upped subdivison level to 0.5 and v3 cloud.