Hi Kenzzo, thanks Dave - really depends on your partners sailing level, but my wife (50kg) rides the FW95 in mainly light wind conditions with a 5.3 Hero on flat water, loves it - sometimes also the 85 if more wind. The STB99 is more of a light wind wave riding board, not the earliest planing board really, so I would stick to the FW as it will feel familiar to your 105 - so either FW 85 or 95 depending on both of your weights and sail quivers etc?