Question on Amphibious Assault Maps

[Pepper]

(1) I have found the function in the map editor to add a beach (p.2, "L" key). However, it makes fully 1/2 the map water. Is there a way to edit the water/land ratio?

(2) If the answer to (1) is negative, are there any problems with simply making a map manually (including water and beaches), and then using it later as a beach assault map (as identified in scenario editing phase)?

(3) Whats a representative visibilty for a night assault under very dark conditions (solid cloud cover)? If each visibility point = 50 meters of visibility (I thought I read that somewhere), would a value of 2 or 3 be appropriate?

Thanks!