You could keep much of the footage Obi-Wan could be meeting with the cloners to negotiate the creation of the army as voted on in the senate (only moved nearer the beginning of the film now that Padme is out of the way).

He could find the army is already created which is mysterious and convenient but less so than having a direct link to the enemy camp flashing away like a big red warning sign.

The fight with Jango and Obi-Wan could instead take place on a landing platform on Coruscant (he could follow him to his ship after he bumps off Zam). Kenobi uses the tracking device to follow him to Geonosis.

There the Clones from the beginning of the film come into play.

So basically much of the same footage (maybe with the cloner's dialogue altered) but restructured so it's less of a twisted brain-wrong of a one-off man-mental.