I read that you don't really need to use a MH lamp for veg, that you could just use a horitilux or san agro HPS lamp from start to finish with the same results. Is this true? Should I use a 400w bulb for 3'x3' or can I use a lower wattage? Also, can I get mylar from Home Depot or someplace? I don't want to waste money on shipping.