Setting up Trellis?

Hey, I am about to build a box and will be using trellis. Question is how high should I set the trellis off the ground? I was thinking 3 feet, or is that even what you go by?

And is one net good enough?

This is for indoors, as well as I would like to keep the plants around 4 feet tall.

Thanks for feedback!

Regards,

If your going scrog and want them to be 4ft then put the trelis at or a few inches below what u want the canopy to be at. You want the whole screen filled not really letting the plant grow above it

Much love and +rep for your response. I am setting it up 3ft above my pots, but I built it on adjustable poles on the 4 corners so that it may be adjusted if necessary