I fly fish a bunch so I went with tops that were only about as wide as the console on both my 18' and 20'. both tops are between 5-6' long from front to back and around 36" wide. I personally thought the beam on these two models was too narrow to go with the 5x7' that many shops have as standard. Here are some pix of my two boats:
1977 SeaCraft 18' -
1971 SeaCraft 20' -
and in use you can see that it doesn't stick out too far beyond my 28" wide console, for a total width of 36" -
