I've had a set for 14 months. They've held up really well and that included a couple of falls and they didn't fall apart. They are waterproof and I know living in the PNW!!! The top case is 40 liters and holds my full face adventure helmet with a visor just fine and measures 15L x 13W x 12.5H, the side cases are 36 liters and measure 17L x 8W x 16.25H. Here is a link to their blog on the view of the base rack mounts:
http://californiascooterco.com/blog/?p=17316. Once you get them you "may" have to make one modification to the base rack...but it's an easy one. If you have a 2016 or beyond RX3 Zong changed suppliers for the rear blinkers on the bike...they are wider than the 2015's so the base rack will cause the indicator to rub and get pushed a bit by the luggage on the non-exhaust side. There is an easy fix by replacing the stock bolt that comes with the kit with a longer one and a couple of nuts....see the picture. The on/off uses a clone of the Touratech pucks and only takes a second to put them on and off. I like this as I purchased Giant Loop Round the World panniers and they come with the option for Touratech pucks so my soft luggage connects exactly the same was as my hard luggage....NICE! I use hard luggage around town and long road trips...soft luggage for offroad adventures. The other thing to be aware of is for the top box, the 4 pucks that slide into the keyhole mounts on the base rack are made of plastic even though it looks like metal. If you do bouncy offroad stuff with the top box on those can break and send the top box tumbling down the trail....don't ask how I know :0). I ended up using a dremel and cutting the bottom portion of the tabs off and replacing them with longer bolts, stainless steel washer and nylon lock nut which I then covered with hot melt glue so I don't scratch stuff when I set them down...now it's all good! As far as the width goes, with the cases being 8" wide and from the pictures you can see the standoff from the bike it should give you a good idea of the overall width. Hopefully the pictures and this info helps. Take it easy!
Joe