Correct distance

Both should be okay. You may want the hps a bit further away due to single point of light needing to spread out a bit more. The tent walls will mitigate any loss from an extra few inches. These are probably good at 66% over 18hours and when you switch to 12/12 just bump both to 100% power and all is well. I'm assuming the HPS scales as welll as the LED does as far as percent power and umol/s production of light. The led might be a bit too powerful for 4sq ft, so if you see signs of light issues dim it slightly from the above suggestions relative to hours of operation. The hps is probably better for ~3sq ft, but should be fine. If you keep the plants away from the walls, that's essentially 3 sq ft. you can use a free klux app or photone app to measure percent difference from center areas to outer edges. Without sacrificing overall average, you want to reduce the deviation from center to edge as best you can. So, lux can help you accomplish this even though it's not an ideal measurement for our context. Expect the hps and led to read differently whether you use the klux or photone app. the photone app is converting klux to ppe/ppf and the drastically different light propreties of hps vs led will impact that conversion. So, don't compare readings under hps with the led, they will likely be different even if they provide the same DLI, which is what truly matters.. DLI is the key. 35-40 dli/day is about as much as you can give a plant without supplementing CO2. Always react to the plant and not what the breeder says. Shoulds, woulda, coulda doesn't matter... if the plant gets leggy, it likely can handle more light. This can vary by plant. There is no one-size-fits all answer, so always react to what the plant says.. it knows better than the breeder. Too many variables for a one-size-fits-all answer.