I still use Zaino on almost a weekly basis as the interior of the SC430 is Ecru or like a cream white! A real pain to keep clean, but as long as you keep a maintenance schedule on it, the leather should remain clean along with common sense.
I did a badly kept Austin-Heley last year with Leatherique. It took many applications and after getting a good start and owner was not driving it, I removed the seats, brought them inside and re-applied Leatherique. This time borrowed my friends paint oven at the shop. Got them nice and hot all around, kept adding the oil several times during the A/H bake-off. Once removed, a good amount was absorbed. Did the cleaner and checked next AM. Damn if these seats didn't look new! Re-installed the seats, owner asked if I had them re-covered, but then noticed a mark that he would only know and was amazed on how well they looked, felt and smelled. He was very happy and continues the treatments for maintenance.
Leatherique is a product you just cannot rush, but time does make it work well and the warmer the leather, the better it gets. Just don't stick them under heat lamps for a long duration or the leather will start to shrink.
For light colored leather, I would advise to test an area to make sure it's OK and not going to darken the leather dye. So far, it hasn't. I always check with Leatherique if you are not sure as to type of leather you have. It's only a phone call and can save you headaches!
Still use the 1Z or Autoglym now and then, but the 1Z has a small amount of carnuba, which can protect the leather from light dirt, but prior to Leatherique, I have to strip the seats with a good cleaner so the oil can penitrate.
Hope all of you take your time and find it as good for you as it is and was me.
Regards,
Deanski