Consider "Drop-In" Unit
Something to consider is resale and being able to get your money out. In the past several months I've been looking for another boat and one I really liked had two built-in air conditioners. Unfortunately, they were fairly new, along with a generator, (guy got divorced) and the seller has a hard time lowering his price. In my cruising area we can easily get by without air conditioning - but heat is important(!!) - hence, we don't want to pay for something we don't need. Not only that but the two units take up valuable storage space.Just suggesting here, but, perhaps a drop-in unit(s) that fit over a hatch could work and when you sell the boat they can be taken off. The downside is stowing the unit while underway.Also, during the cooler weather the storage space could be used to accommodate items to keep people warm. Storage space on boats, unlike say, RV's, is very limited. Another advantage is fewer holes sawn in teak finished bulkheads.