Hi mike, soft plastics definately work at night, but it's important to consider that they are not as visible to the fish as during the day - so vibration and scent play a much bigger role. Try and use SPs which vibrate, eg. shad tails, and use a scent on your SP, or alternately use GULP SPs. A plastic I reckon will work really well at night is the GULP shakey shad - it has the scent of GULP and also a big shad tail to send out lots of vibrations <img src='http://www.squidfish.net/forums/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt=':o' />
Nightime lures worked as topwater lures are better if black coloured since the hunting fish sees the lure from below in silouette against any moon or ambient light.