hey 4x
i know what what xxx is and a buddy explained 5x = yuck
so, what is 4x then ?? {scared to ask

}
using james' windcalculator - for your weight
a 129 liter sailboard will be fine
a 5.8 will be ideal in 17 knots/20 mph/ 32 kph winds
i call those mid winds cuz i go out in light winds with longboards
so, it all depends on where you go and you already have some experience
i always hear the GO 155 is good starter and then more for heavyweights
you seem to be neither
so, since i hear only good things about the Futura 133 and based on some discussion above, i would deduce the Futura sounds like the right choice for you
{based on available info here}
hope others with more SB experience and in your weight range chime in
for me any TOW = good times
a bad day on the water is still better than a good day at work