Bruce, We have had our AT-34 for about two years with no dinghy. We really like using the swim platform for entry/exit of our boat. We also do a bit of stern ties and side ties to other boat(s) and it is easy with this boats platform. With the Tanner davit or similar, you cannot use the center transom door without removing the starboard tie back and lowering the dinghy a bit. Since you are building, you can request a starboard side stern door instead of centered. This may allow you to just remove the starboard tie back support to use the swim platform with a Tanner davit (ask Kurt Dilworth at the factory). We have spoken to a few AT34 owners with the Tanner davit, and it is a good unit but they would prefer a different style or a crane. We are shopping now for a davit for our trip up to British Columbia this summer and will buy either the Weaver or Seawise tilt up style. Also, on the AT34 we are limited to 350lbs for the dinghy & gear. I assume the AT39 is the same since they are the same hull except yours is stretched 3'. You will really like the boat!