A candle begins at bar start plus bar offset and has the width of one bar period.
This is if historical 'ticks' are granular enough and exist with timestamps at BarOffset.
But M15 bars loaded from brokers are for regular periods (xx:00-xx:15, etc).
If 1/2 of the long Lookback period exists in a historical file and is PRELOADed, and 1/2 has to be completed from a broker - how will Zorro create (BarPeriod=60; BarOffset=6) candles for the Lookback ?
