As related elsewhere, my last 2 oopsies left me with a credit for a new windscreen to replace my 1st generation Skidmarx and said Skidmarx screen broken in half, respectively.

After some deliberation and exchanges with Mark from CalSci (thanks Mark) about the size, I had my dealer order the medium one, which arrived about 1 week and a half ago. I've now had some time to compile some first impressions.

- Nice packaging, though the royal blue storage pouch and orange microfibre cleaning cloth aren't in the appropriate Moto Guzzi colours

- installation: simple, the holes are in the right places (more so than on the Skidmarx I had), but where that one and the stock screen are too curved, the CalSci screen is considerably too flat. It required substantial help to get the curvature necessary to fasten the bolts all the way. I hope this doesn't generate too much stress on the risers and (esp.) on the plastic washers. (Q: does the Breva screen still come with idental washers in stainless steel??)

- Something's asymmetric with my screen or my bike: the right mirror touches the screen at (almost) full steering lock. I filed some off the screen, but I estimate there were about 3mm excess material, whereas on the left side there's a margin of about the same size.

- Something vibrates in the fairing at idle, haven't traced it yet. Doesn't appear to be the subframe, though holding the dash does reduce the sound. Pressing towards the right on the nose cone close to where the screen riser exits from the fairing removes the sound, which fits with the fact that the bike reclined against a fuel pump with the right 'cheek' during my last oopsie.

- The medium sized screen is about 5mm shorter than the Skidmarx screen, measured from the fixation holes. It is much wider though, but also descends less under the holes. Aesthetically speaking, I find it less elegant, but OTOH it is much more transparent (note to self: will need to be cleaned much more often than a smoked screen )

- While riding: incomparable. The high frequency shake I noticed over about 110km/h is almost completely gone, and so is the bit of turbulence I had around my helmet (which was rarely a nuisance). I'd say it is an improvement, butI haven't yet decided whether I do not also miss those sensations. Things may have gotten a bit too quiet on a relatively windless day, to my taste, I haven't yet decided. It is clear however that I'm still getting a mouthful of fresh air when there *is* wind. I'm also not sure yet if, despite the bigger calm, I can ride with my visor one click open at the same speeds I used to. Guess I'll be fiddling with the height setting to find the best compromise.

I picked up their medium (+2.5" screen height and 4" width) also for my Norge. I got it off eBay to try figuring if I did not like it I would not lose as much. Being 5'4" tall it was too tall for me. I took it to the local plastics shop and had 2" removed from the top. I just got in a 260 mile ride today and I must say it is much better than stock. I rode mostly with it adjusted not quite all the way up so I could look over it which is what I prefer. Much less turbulence. I can get almost none if I want to look through it but I am no fan of that. I already lost one adjustment motor, under warranty, and it broke while parked at a Guzzi dealer showing a customer how it worked. They are as cheaply made as possible but the way the mechanism is made I don't think the additional load while riding will harm it. Adjusting while riding may but the way I see how mine broke is the screw on the motor snapped like there is no stop for the motor at top or bottom. It looked over torqued. I guess it is the same motor as some scooters. I am now very careful at maximum or minimum heights.
Your rattle is probably the linkage to the shield. It is on mine and the amount of rattle varies with shield height. A few friction washers would have stopped that but with the severely under engineered motor the extra load would probably do it in.

I identified the rattle a while back already. Something with the way the screen was made (cf. the fact I had to bend it) seems to push the left screen riser against the cut-out in the nose cone and inner fairing. That, or my replacement subframe was bent ever so slightly when the bike went down after being rear-ended, last year. It's pure friction of plastic against metal. Probably a bit of black plastic tape (chatterton) will reduce the phenomenon.