it may be unothodox but i found welding vertical to be a big help in getting the hang of controling the puddle. when it was flat on the work bench the puddly just kida sits there and can burn threw befor you notise. as soon as i got tired of playing with lil squares and atempted my cart project i lerned a lot more. you realy need to keep the puddle under controle when moving acrost the side of the aluminum insted of going flat. you lern to use the torch to pull the puddle where you need it, not just get it wet and add to it. kinda hard to explain but you should try a few vertical welds. just to see how the puddle can be pulled by the torch to get it to stay where you need it. it may not help you as much as it did me but it cirtenly cant hurt any. i think you will find it verry helpfull. you kind of have to use the torch like a magnet to pull the puddle, hard to explain but you will see it when you try it.
4Hrs with some one that knows what they are doing will be a big help. in the mean time try the vert. thing just for fun see if its any help. you have to get hot fast and controle it at the same time. your amps need to be high enough to melt threw fast when full on.