Eighteen hours of light in veg is the common default, though twenty four also works and mainly wastes electricity for marginal gain. Indicas respond well to a shorter veg because they fill out sideways rather than upward, and the schedule notes on https://kushindicaseeds.com explain when to flip based on plant height rather than a fixed date. Flipping too late is the usual mistake in a small tent. Two weeks of veg is often plenty.