I was a bit apprehensive about the stiffer bristles as I commenced my leather cleaning last night.
I wet the leather down with the 6:1 diluted Woolite via a spray bottle. As I began to scrub and noticed no scratching nor ill effects, I proceeded to work the solution more vigorously. I had a cloth, saturated with water, which I used to wipe off the soapy residue after I was done scrubbing each seat. I then towel dried the remaining water. The seats dried completely within 15 minutes.
Unfortunately the sun was setting as I proceeded to apply my Zaino leather conditioner to the freshly scrubbed surfaces. This morning I was astounded to see completely rejuvenated upholstery! What looked appeared to be major cracking and flaking was simply years of dirt trapped deeped in the creases. The cracking that did exist was almost invisible as the crevices no longer contained dirt. And because of the thorough cleaning, the leather was much more accepting of the conditioner than ever before. Thumbs up to scrubbing with Woolite, and a big thank you to those at Autopia who suggested this.