In my opinion,4 feet is way too far away. I would not want to be more than 18" or even 24" away, at the very most. Moving it closer daily.
Videoman
Whilst you're perfectly entitled to hold your opinion, if you're going to do so in direct disagreement with one of mine you're going to have to come up with something a lot more substantive than 'that's my opinion'.
The more experienced growers here with good reputations for being helpful need to be doubly careful that the advice they offer less experienced growers is not only correct, but specific to the question being asked.
The problem here with your answer is that it's based on a rather simplistic 'rule of thumb' that you seem to have adpopted and that is that the closer the light is to the plants the faster they'll grow and 'plants can never have too much light'. In most situations apart from seedlings and clones those rules of thumb would apply, but not to seedlings I'm afraid.
Seedlings with their first set of cotyledon leaves are still using stored energy supplies and aren't even photosynthesising yet, so why do they need so much light? Too much light at this stage can actually stress and kill the delicate seedlings.
Seedlings and clones only need about 500 lumens per square foot for perfectly healthy growth to take place. A 250w MH will output somewhere around 18-23,000 lumens with HPS's more mid 20's. Even 18,000 lumens at 4 foot is outputting 18,000/4x4=1,125 lumens per square foot, which is already double the recommended 500.
Environment, temperatures, photoperiod, humidity, nutrient levels, planting density can all have an impact on the amount of stretch seen in seedlings - low light levels is only one cause and as long as the 500 lumens per square foot is adhered to shouldn't be the cause of stretch in seedlings.
As soon as the first and second pairs of real leaves appear then photosynthesis is starting to increase and the light should be lowered to give the young plants about 2,500-3,000 lumens at the plant tops. For a 250w MH, that would be 18,000/4= 4,500, 18,000/9 = 2,000, so about 2 1/2 feet away should be the optimum distance for early vegetative growth. As soon as 4 or 5 nodes have shown this can be lowered to about 2 feet away.
I certainly wouldn't advise anyone to have a 250w MH only 18 inches away from delicate seedlings.