guitar cabinets modified for harp

hi david

i saw an ad for a 4x10" guitar speaker cabinet

i presume the back is closed

is there a way to make the cabinet better for harp?

      also is there a formula for the amount open space in the back and where the open part is?

just becasue the cabinet is not expensive, doesnt  mean in the end this is the way to go

what do you suggest?

also, the cabinets that mark overmann is now selling, i have heard have a smaller open part in the back

if i were to ask him to make a cabinet for me, how much open space in the back would you suggest i ask him to make?

thanks,  as always

tommy