I'm in the process of pulling the cab set on my 1100. I'm finding it very hard to locate the drain screws/plugs, while the carb set is on the motor. my plan is to pull the set, without inverting it. and drain and then clean out the bottom collected crud, before inverting the set for the intended work. this means that I'll have to unscrew the bowls from the bottom. difficult enough with the right tool. so my question is- what size to buy for this task? is there a simple apex type of tip available or does this require a true screwdriver? and what size to buy?