Sorry I didn't check ur level and clubs before posting this, but I have the best clevelands, 56º = 100 yards, 60º= 80 yards and 64º= 60 yards.
For 30 yards I can spot it ( within 3 feet or less ) everytime playing a full shot and hitting 60% power. Obviously you have to take into account wind elevation and slope on green, but those will be minor adjustments for such a short shot.
Equally good is the 29 yard flop with the 60º wedge, adding back or top spin depending on the situation.
As YJ says the ratio of power to distance is not linear, e.g 75% power on my 64º will give me 40 yards and the punch gives me 50.
So 20 yards = flop
30 yards = 60% full shot
40 yards = 75% full shot
50 yards = punch
60 yards = full shot 100%