Having sailed far offshore on a pilothouse with large port/windows in the pilothouse here is my take- Lexan- expensive, strong, scratches easily, especially hard to see out of at night. Plexiglass- relatively inexpensive- really not suited for larger expanses since it will flex and blow out when hit by a big wave. Tempered safety glass, stiff, optically good, heavy, will break with hard impact. The boat i sailed extensively on had forward window in Lexan(because of hatch in window) and the side windows were 3/4"" tempered glass which withstood several days of waves crashing over the pilothouse. Good luck with your choices.