For fashion shows, it depends.
A "real" fashion show would need 2 to 4 DOZEN lights to do right. No LED's unless they had a very good white with a high color rendering index. No gel unless it is used for color correction to match follow spots or movers for video. Models will be use to bright lights.
Non pro/charity fashion shows can pose all kinds of other problems.
Non pro models may not tolerate lights in the eyes. To deal with this I have used lights out front but off to the sides. Shuttered from the neck up on average height models. I have also used many lower output lights to lessen the brightness of each light in there eyes.
The "powers that be" may have different ideas as to what areas of the stage are important. Some want the whole thing, some just want the front. The very back is often just an entrance / exit area and may not need to be light up. Try not to blind the spectators on the opposite side of the runway.
I have done small, nonpro, fashion shows with as few as 2 S4-50 just as face fill for video. That sucked for light and I would not recommend it. 12 par 56-300 worked well. 6 each side about 45 deg off the end of the stage 10 ft up. 3 per side S4 MAY work or 2 per side and 2 head on may also work. It depends on what is important, the room, and if the models will work with it. This is the minimum, just to say there is light.
Always have the lights ready for the final rehearsal. The models will need to get use to them and it gives you time to make any changes. The goal is even white light to show off the clothing. Minimum shadowing on the clothing is best. Never color on the clothing. Some glitz and color on the back of stage is fine.