I use the following formula, it has worked well for numerous clubs and shot types that I've tried it with. Charting the clubs and shot types first is recommended. It's accurate with a club power between 50% and 100%.
I use it with full, punch and flop shots. It semi-works with pitch until the green/spin take over, doesn't work well with chip shots.
(((clubdistance - shotdistance)/4)+shotdistance)/clubdistance=percentage of clubdistance to hit.
Subtract your estimated shot distance from your clubs max distance, take the result and divide by 4, take the result and add to your shot distance, then take that result and divide by your clubs max distance. This will give you the percentage to hit the club for.
90 yard shot with a 100 wedge.
(((100-90)/4)+90)/100=.925, or 92.5%
45 yard distance, with a 60 wedge.
(((60-45)/4)+45)/60=.8125 or 81.25%
30 yard shot with a 60 wedge.
(((60-30)/4)+30)/60=.625 or 62.5%