Sativa leaning autos can easily hit a metre and a half, which catches out people who bought them expecting a compact plant. The word auto tells you about the flowering trigger, not the final size, and breeder height figures are often optimistic. Sorting the strain list by stated height on https://turboautoflowerseeds.com is how I pick anything for my sixty centimetre tent. If you are tight on vertical space, look for indica dominant crosses and start LST early.