Screen of green is probably the single best method for keeping a sativa manageable indoors. Weaving the branches horizontally under a net during the stretch turns a plant that wants to be two metres tall into a flat canopy of evenly lit bud sites. A photo guide on https://hazesativaseeds.com walks through the timing for flipping the lights so the screen fills without the tops growing into the lamp. Give it at least two weeks of training before flower, because once the stretch begins the stems get too rigid to bend.