[Frank Messina]

You've probably got a couple things going on there as far as your tuneup is concerned but I'll just address your PV questions. First if the power valve is leaking, the backside of the metering block will be wet from gasoline when you pull it away from the body.
Next there are a number of simple formulas in use to help decide which power valve to use. Everybody's got their favorite. One is take to take your highest steady state vacuum reading at idle and divide by two. So with 16" at idle, using this formula you'd want an 8. Another method says to divide by two and add two. So 16" divided by two plus two is 10". This means when engine vacuum drops below 10" the power valve opens and adds more fuel. Likewise the 8" PV won't open until vacuum drops below 8". This gets you smoothly up over that long hill when your cruisng along. When you mash the throttle though it doesn't matter what you have in there because vacuum goes to zero and the power valve opens. What you have to be careful of though is if you have too low a number PV in there, as the engine vacuum begins to recover, the PV can close and cause the engine to go lean. The car will feel like it's nosing over. Not good. Take your pick though, both methods will work, just give the motor what it wants.
As far as your no power hesitation is concerned, you've got some other tuning issues to address. HTH
Frank

PS: The only thing a high float level will do is cause a rich/poor idle. Set the floats with the engine running so that fuel just dribbles out (not shakes out) of the sight plug holes.