There's nothing wrong with the Tortoise: those who mock it have perhaps never used one, but it does tend to be a bit splashy in a chop, which can make for wet rowing. What do you expect from such a short boat? Ours served us well and faithfully in the S America, the Falkland Is, South Orkney and South Georgia and is possibly the only tender to have been hauled up by the crane on Gough I! There are probably better designs, but I found it more impressive than the Elegant Punt, which I thought a bit disappointing. If not as disappointing as the smaller of the two Nutshells. The Nymph is a delightful dinghy, but designed, I think, for 7'6"; the 6'1" Scraps is probably both stiffer and more buoyant. And a bit wetter in a chop.
The main drawback with a nesting or folding dinghy is the sloth of the average human being. Having to put a dinghy together effectively discourages one from going ashore and, perhaps even more importantly, from hauling the dinghy on deck with the result that you will end up towing it when you most certainly should not be.
Personally, I don't think davits are a realistic option on your wee boat.