This is totally up to each individual, but I would dump the gw and sw, instead plug a 54 wedge with mid bounce, somewhere around 10*...but again, this is my preference and also dependent on the bunkers I normally encounter...if I played in fluffy bunkers, I'd need a bigger bounce....

I'd also take a look at why you hit the pw and gw a club longer than you do your 56...is it ball position? Is the ball position such because of the bounce on the 56? Are the clubs swingweighted the same or is the 56 heavier (as they tend to be off the rack)...is shaft length part of the equation as to why the 56 is disporportionately shorter? these are questions I'd answer before buying a new club...