I got a Sargeant seat for mine - converted it to std GS format. You can also buy Adv style one piece ones too now.
Very comfy, better than std seat, but noticeably lower. To the extent that I've reverted to the std Adv seat until I can get some spacers made to raise the Sargeant seat up to the Adv height.
There's a good 15mm difference, if not 25mm, despite what they say on their site about it being same leg to pedal length, despite being slightly lower (they reckon it's wider and that makes the leg length the same, but I don't think so)
That, or I might buy the Sargeant Adv version if they can make it the same height for me.