I did this on my last camper set-up. The space in front was primarily for a Honda 3000EU generator. There was also access space on either side of the camper forward of the wheel wells. Welcome space for firewood, empty beer cans, other...
The spacer was built custom for the generator making sure that the back part of the camper did not touch the rear tail lenses. If set up properly, the COG will still be the same as if the SB camper was installed on a SB truck- this is because the axles location from the rear bumper is the same on either truck. My COG was still forward on the axle by about 2" even thought the camper seems to appear further back.
The rear tie-downs were for the most part straight up vertical, but this was just keeping the back of the camper in place. The front mounts were angles more and I needed to extend the connection point about 4" with chain... it did allow access to the fuel fill door without needing to remove the fasteners.
If anyone is considering this on a DRW truck, it might be prudent to analyze the fitment of the fasteners first before diving in as they might be affected. A SRW will have less concerns about conflict of fasten to fender wells.