24 inches is too small IMO.
Then again I like to get, at minimum, a half lb per plant for my larger yielders.
LST the shit out of it w/ Scrog like you said. You will be topping the plant and as a beginner the cut can be difficult. Quick and clean. Don't think about it too much.
Grow just 1 at a time and figure out what you're doing. Fox Farm liquid nutes are nice. You can use empty milk jugs to PH balance your water (6.5-6.7) and also check the PPM and adjust accordingly + add your nutes so you can readily feed your baby. Don't let her grow in to the light and wrap around it. Roommate killed 2 babies when I was out of town cuz retarded letting this happen. They have intense growth spurts randomly. Be prepared as another user mentioned.
Last and most important, flush your plants 2 weeks before you chop them down. Run clean PPM/PH correct water thru them only. Removes chemically taste from buds that is associated w/ a plant full of nutes. Also, invest in a trichome microscope. Idk what they call them, but it has a light on it and you can focus it to look at the trichs. When they start to get milky white is when you know it's about time to chop.
Good luck it's fun and eZ.
P.s. the bigger the part of the plant you CANT see, the bigger and better the part of the plant you CAN see is
