I use 1588 belt on 1UZ vvti (UCF21 celsior) : only A/C is deleted, hydro fan is functional
The belt lasts for 3 months of everyday use and then starts to chirp badly. The mark is at the minimum tension (lower limit of range B, middle of range A according to factory service manual)
Still unsure what other length to use as most people here seem to run LONGER belts while I need a shorter one apparently