Renat, I've seen lots of people with lots of stuff hanging off the transoms of older boats and to my mind it's somewhat awful. Do bear with me a moment longer--
Why store the dinghy on davits just at a mooring? I use a 9-ft piece of lifeline cable, two inflatable fenders and a padlock. I mean,
duh. (As a backup I can always add carrying a shotgun to that combination.) My inflatable folds up and sits either on the foredeck or on top of the hatch shroud.
I'll grant that the steering vane is a great benefit; but it's still weight and complexity. It would likely foul the dinghy on the davits; but if you say you're not going to sail with the dinghy on there (freeing the wind vane from fouling it). then why have the davits at all? At sea (where you're going to be sailing with the windvane) a dinghy on davits is a major liability on any boat that can be small enough to be affected in trim by the dinghy being there. The dinghy makes the boat ride stern-low (not good in a seaway), makes it steer slowly, inhibits sight aft, and worst of all carries the threat of its becoming full of water in any great slop. In a situation like that (dinghy on davits, high rolling waves, getting pooped), your best-case scenario might be for the davits breaking off the boat. Little else seems desirable to me (read Steve Dashew again!). Again, I have to wonder
why. Davits are all right on a boat about 45 ft and up, carrying a small (8-9-ft) dinghy. On a 30-ft boat I think they're way overkill, and downright inefficient and even dangerous.
I have an H25 and for years have been looking for a rigid 7'6" dinghy, just big enough for me and the ice and.or cooler, that can stow on the foredeck, allowing me room to have access to the stem and the anchors. I have found nothing affordable or adequate. I am left with the undesirable 'option' of towing a slightly-larger rigid dinghy down the ICW and leaving it at a friend's house, or selling it, when I cross the Stream to the Bahamas next year. I don't like rowing the inflatable (I tend to row it kneeling, facing forwards) but it really is the best option for anyone with a smallish boat. Most of them tow really well (close in and bow high) and hold their own if they get slightly pooped (such as when crossing a big bay, like the Ablemarle).
The best reason to have solar panels on davits is because they're typically in clear sun there and they're adjustable. But that 'picnic table' array of solar panels is itself bad windage and weight too far aft; and in a bad blow they're likely to disappear anyway. Again, I would look for a safer, more sensible compromise, such as mounting them on the cabintop, that takes into consideration the 'worst-case-scenario' cases that are entirely likely if you're sailing offshore (otherwise why the wind vane?).
Two more options you may consider are:
1. Flexible solar panels that pull up, like with a halyard. Put them in the best position, like against the mainsail under way or across the mainsail cover when in port, take them down otherwise and rely on smaller fixed ones to do regular work to a lesser degree. Prices for these have come way down in the last 3 years.
2. Autopilot. If you must go with a major array of solar panels, coupling that with more batteries you'll have the power for a small autopilot. Will Keane at Edson holds seminars in which he asks, 'How many of you have an electrically-assisted emergency tiller?' No one raises hands. Then he asks if they have autopilot.

Whilst the wind vane is, in effect, a reliable emergency tiller, it's also more vulnerable than the rudder the boat came with. Having a completely separate autopilot (running on its own cables or ram), you have the desired redundancy and self-steering capability. Best, for a smallish boat it doesn't take up space on the transom and doesn't add much weight.
I think that's the first time I've ever lobbied
against a windvane self-steered! --but if it requires adding 250 lbs to the transom of a 27-ft-waterline boat, maybe there's something in considering more options.
I'd be interested to discuss this with the professional techs who recommended the davits/solar panels/windvane mounting that flexes your transom so badly.