Dave, if you are just "screwing around" with the Norvel big mig you should be able to get a decent run with the needle provided on bladder pressure. "Even on suction it is coarse"? I fly them all the time with suction , no problem with the coarse needle. On a flying platter with a Big Mig and a balloon tank set fairly rich for launch i can get a pretty good 2 4 break and do some taildraggin. I have two ame's and two big migs on combat planes with bladder pressure, they can be a litttle touchy, but quite useable! I find that if from time to time i blow out the spraybar with compressed air they will work fine. Might try different types of bladder material to get the right setup, some can create more pressure than others.