G'day Prokop,
I hope you won't mind me sticking my bib in now you've reached your setup stage.
K model Hondas have a relatively short wheelbase used as a sidecar platform.
Your chair looks fairly wide so I'm assuming your track is wide relative to your wheelbase.
If your interested in a discussion on setup and maybe a couple of initial riding tips let me know.
If not I'm happy to keep my nose out.
Cheers,
Brian