There's one thing I don't get: so reportedly after the PS 85, he used a custom 90, then the actual PS Tour 90, and then his custom 90 (the 'Kfactor').
But what was that first custom 90, then? Was it the Kfactor model already? Then why did he switch back to the PS Tour for a while? Or was it an unknown 90 model that would develop into the PS Tour?