There are no boats in the BVI without biminis, and most of those also have a roll-up or otherwise detachable flap aft which can be let down to block off the late afternoon sun (winds there come from the east, so the stern is usually pointing roughly at the setting sun when at anchor). I took my bimini
down a couple of days before putting the boat on the hard
and that was a huge mistake, the cockpit
suddenly was no longer a place of comfort... more like sitting on top of a broiler.
is optional. I liked it when sailing upwind to keep out the most of the weather
. If the dodger covers the main companionway
then go ahead an do it, that way you can keep the main ventilation open even during the frequent rain showers at night.