i think with the full scale launcher you should be able to fit a car battery in the mid section, it will make it heavy but less wires, as far as the video goes i wasn't too impressed but thats probally cuz i don't like the look of the guy firing it...... by the way the longer the rocket the more stable it will be, and i would recomend putting two guild rails inside the tube just to help guide the rocket out of the tube, and MAKE SURE that all your fins are STRAIGHT AND LEVEL or else u'll get a rocket that goes everywhere which goes without saying can be dangerous