[…] Jango then goes to Geonosis specifically to lure Obi-Wan there, so that Dooku can take him prisoner.
Why does he try to kill him in the asteroid field and leaves only when he’s sure he died, though? Supposing this was part of the plan, I think Jango really wasn’t aware of it.
EDIT: It may be that Palpatine’s plan was just to reaveal the existence of the clone army for the Republic, so this would explain why Jango tried to stop Obi-wan from getting on Geonosis. Some time later, they would’ve eventually found out about the droid army anyway, maybe by Dooku himself.