The twin has an 18inch front fitted so from an earlier GSXR. I would suggest that anyone doing this not use 750 rims. Even when they were new they bent easily. Use 1100 rims if you must have 18 inch, they are much more robust. Back in the day we had a guy who worked from home who straightened usually a wheel a week for the shop.
The front rims were blamed for certain issues concerning the handling of early 750GSXRs, they certainly are lighter and weaker than those used in the 1100. But certainly not weaker than Laverda cast wheels, the early type would buckle while just swerving to avoid a pot hole...
The beauty of these wheels is that they are non-directional, they do not look out of place in the rear of a Laverda with its opposite-side drive. As a bonus, the spoke pattern is quite similar to the Oscams fitted to the SFC1000.
I have used the 750 GSXR wheels in both my 3C and RGS without issues. Especially the RGS is a barge compared to the donor bike, but the wheel(s) have stood up fine over the past 20-odd (is it really that long ago??) years. I now use a 2.75" rim from the 1100 in the 3C, the RGS still has its 2.50". A 150 rear tyre is about the largest that fits without great issues on either a 4.00" or 4.50" rim, a 160 or larger will require the use of a #520 drive chain, preferably of the non o-ring type. The 130/80 on a 4.00" in my RGS works fabulously, nice contour with great mileage from the humble BT45. Current Conti isn't standing up so well.
For additional tyre clearance, a SF750 swingarm can be fitted to a triple. This needs slight mods, but is mostly plug'n'play. The RGS swingarm offers slightly more clearance than the stocker, but is longer and definitely not plug'n'play.
Modifying these wheels is not for beginners and not something that is accomplished on a Saturday arvo while downing a case of coldies. Modifying the speedo drive to fit the front is tricky and a rear sprocket needs to be custom-made.
Imho, the mod is well worth the effort, the dramatic decrease in unsprung weight transforms the old clunkers into decent handling, chuckable toys, offering decent brakes and wide choices of modern(-ish) rubber. Sadly, this will quickly showcase other chassis deficiencies, so the story goes on and on...
To each his own regarding tubeless tyres on stock Laverda wheels. This was warned against by almost all manufacturers using cast wheels and tubed tyres, the reason being that the profile of the rim is generally unsuited for tubeless tyres. That tyres do not imediately jump off stock Laverda rims is due to the fact that these wheels were apparently made to upper tolerance ranges, something that anybody that has struggled removing/fitting tyres to these wheels can relate to. However, the later version of these wheels can safely be machined to properly accept tubeless tyres, making tyre fitting as effortless as with any other modern rim.
BTW, the 750 GSXR-R Limited Edition was equipped with the wheels and brakes from the 1100.
piet
Rode another couple of kays to my uncle's workshop and bludged a tyre valve and some air! 
No issues at all with de-beading.
