About the shallows yes a definite puky green there he he
I paint in Gimp on Mymap_c using various rgbs from rgb 50 - 70 in varying thicknesses I use a brush of one, three, and five pixals around the coastline, river fronts and islands etc.
Blur mymap-c a couple of times.
After you think it looks good save it and make a new map_c and map_c _table with map_c tool box.
Then Bombsaway has created a magnatitude of interesting shallow textures. His instructions are very easy to follow mainly changing Water textures in the load.ini and correctly placing his shallows texture in the right _Tex/water folder.
He has a number of different textures available in the Textures section here in map works.
Very easy to slot in after painting on Mymap_c. My Northern Borneo map only took a couple of hours to do.
Hope that helps.
About the frame rates the palms are a major killer I try and use others like bananas etc.
But hey you have to have some palms especially on a Pacific map.
Frame rate dropage for me is not a problem I like detail and enjoy flying low and buzzing cities and towns.
You never know what you'll be able to see flying low over a main street perhaps a couple of dogs fighting
Hope the info for re doing the shallows will help