Under the frame you will find a small (drainage?) hole.
This is also, roughly, the centre of balance for the S40 when road ready.
More or less directly above that point is where the handlebar connects to the boom.
I suspend my bike from a rope and hook at that point, it's level and easy to work on.
A bike stand is something I run hot and cold about, this method is so easy.
Disclaimer
I have a Rolhoff up front which does alter the weight/balance a bit and
I use a 'Steer Stopper' to prevent front wheel flop.
Sometimes I have to work on my bike in the field when touring and a bit of para-cord tied
to this point and a tree branch works just fine.