Hebie steel bipod. You also need to have a decent kickstand plate. An alternative to the latter is a Hebie accessory that attaches to the chainstay bridge.
Yes, admittedly I did opt for the generic alternative. I suppose the main difference would be how wide the stance is. Mine is 22cm (8.5 inches).
I also agree one plus of a bipod is that, as one wheel is elevated, it makes it very easy to turn the crank and oil your chain.
Can I ask you a question about the kickstand plate? How does it attach to the bike? Are all part included for mounting it or is there additional bits to purchase?
I actually purchased a Herbie 636 on ebay but when I realized it needed a kickstand plate I cancelled the order and got a wide generic kickstand. It mounts the "standard" way, in my mind, sandwiching the frame behind the bottom backet. I suppose, if I had to guess, a kickstand plate is less likely to have lateral movement from a loose bolt. I don't know how common they are in Europe, contrary to misconceptions that all European have these Dutch bike extras. My bike is German but a kickstand plate and bosses for a ring lock aren't there... it's uncommon here too.