Hay poker2 i am glad to see your 1st experience was fun and you are keen to have another crack at it. My opinion would be to go with the 600 w both HPS And MH, if you are only doing a few plants a 600 w is the best bang for your buck. Regarding yield i would go grab some organic nutes for both Veg and flower, there is plenty of info regarding the different mediums and what would work best for you. Regarding a grow tent or make your own i would make your own, then you can make it to whatever spec you require. I have just started my own grow not that long ago and its not going as well as expected but the wealth of knowledge on this site & others has helped me get back on track. K.I.S.S theory works well. ( Light, Fresh air in, Hot stale air out, PH, Food ) I hope you enjoy your grow a bit better this time around & have a bumper crop.