How many LED strips is a loaded question. Are you growing seedlings? Mature plants? Are you using growing lights to get an plant started for eventual transplanting outside or are you aiming to produce a crop from germination to harvest indoors?
The benefit in your equation is that your growing space is limited. The module itself is 24" long and if it were me I would start by prototyping by using one module for every 6 square feet of area. You may be able to increase your efforts by using reflective surfaces to help bounce the lights back to the plants. (In my indoor home garden I used aluminum foil or put the assembly near a mirror) If you find the plants are spindly, try lowering the lights to the seedlings or increasing the number of LED modules.
Hope this helps.